Language：English   Publishing type：Research paper (scientific journal)  

Metal-organic frameworks (MOFs) with versatile functionalities have applications in environmental science, sensor separation, catalysis, and drug delivery. In particular, MOFs used in drug delivery should be biodegradable and easy to control. In this study, spray-dried cyclodextrin-based MOFs (CD-MOFs) with tunable crystallinity, porosity, and dissolution properties were fabricated. The spray-drying precursor properties, such as ethanol volume ratio, incubation time, and precursor concentration, were optimized for controlled crystallization. On the basis of the morphology, X-ray diffraction peak intensity, and specific surface areas of the spray-dried CD-MOF products, they were categorized as amorphous, partially crystalline, and highly crystalline. An active pharmaceutical ingredient ketoconazole (KCZ) was introduced into the precursor to prepare KCZ-containing CD-MOFs. The surface areas of these products were greater by 3-fold (292 m2/g) than that of the plain CD-MOF (94.1 m2/g) prepared using the same parameters. The presence of KCZ in the hydrophobic cavity between the two γ-CD molecules was correlated to the CD-MOF crystal growth. Additionally, CD-MOF particles exhibited different dissolution behaviors on the basis of the position of KCZ in the MOF. These spray-dried CD-MOFs with tunable morphology, specific surface area, and dissolution could have potential applications in various fields.

DOI： 10.1021/acsabm.3c00162

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HClO is typically manufactured from Cl2gas generated by the electrochemical oxidation of Cl-using considerable electrical energy with a large concomitant emission of CO2. Therefore, renewable energy-driven HClO generation is desirable. In this study, we developed a strategy for stable HClO generation by sunlight irradiation of a plasmonic Au/AgCl photocatalyst in an aerated Cl-solution at ambient temperature. Plasmon-activated Au particles by visible light generate hot electrons, which are consumed by O2reduction, and hot holes, which oxidize the lattice Cl-of AgCl adjacent to the Au particles. The formed Cl2is disproportionated to afford HClO, and the removed lattice Cl-are compensated by the Cl-in the solution, thus promoting a catalytic HClO generation cycle. A solar-to-HClO conversion efficiency of ∼0.03% was achieved by simulated sunlight irradiation, where the resultant solution contained >38 ppm (>0.73 mM) of HClO and exhibited bactericidal and bleaching activities. The strategy based on the Cl-oxidation/compensation cycles will pave the way for sunlight-driven clean, sustainable HClO generation.

DOI： 10.1021/jacsau.3c00066

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DOI： 10.1016/j.micromeso.2023.112550

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Language：English   Publishing type：Research paper (scientific journal)  

Laminar membranes comprising graphene oxide (GO) and metal-organic framework (MOF) nanosheets benefit from the regular in-plane pores of MOF nanosheets and thus can support rapid water transport. However, the restacking and agglomeration of MOF nanosheets during typical vacuum filtration disturb the stacking of GO sheets, thus deteriorating the membrane selectivity. Therefore, to fabricate highly permeable MOF nanosheets/reduced GO (rGO) membranes, a two-step method is applied. First, using a facile solvothermal method, ZnO nanoparticles are introduced into the rGO laminate to stabilize and enlarge the interlayer spacing. Subsequently, the ZnO/rGO membrane is immersed in a solution of tetrakis(4-carboxyphenyl)porphyrin (H2 TCPP) to realize in situ transformation of ZnO into Zn-TCPP in the confined interlayer space of rGO. By optimizing the transformation time and mass loading of ZnO, the obtained Zn-TCPP/rGO laminar membrane exhibits preferential orientation of Zn-TCPP, which reduces the pathway tortuosity for small molecules. As a result, the composite membrane achieves a high water permeance of 19.0 L m-2  h-1  bar-1 and high anionic dye rejection (>99% for methyl blue).

DOI： 10.1002/smll.202300672

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DOI： 10.1016/j.jcis.2023.01.143

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Hydrogen peroxide (H2O2) has received growing interest as an energy carrier. For the development of a sustainable energy society using H2O2 as a hydrogen carrier, the photocatalytic H2O2 splitting into H2 and O2 is a desirable reaction for the generation of H2. This reaction, however, is difficult to promote because the photoexcited electrons reduce H2O2 to H2O more preferably than the H+ reduction, thus suppressing the H2 generation. Here we report that visible light irradiation of Nafion-coated graphene quantum dots/carbon nitride (Nf-QD/CN) photocatalysts promotes the H2O2 splitting. The surface Nf layer on the catalysts behaves as an H2O2-impermeable/H+-permeable membrane to promote the H+ reduction while suppressing the H2O2 reduction, resulting in the H2 generation.

DOI： 10.1016/j.jphotochem.2022.113949

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Photocatalytic generation of H2O2 from water and O2 under sunlight is a promising artificial photosynthesis reaction to generate renewable fuel. We previously found that resorcinol-formaldehyde resin powders prepared with a high-temperature hydrothermal method become semiconductors comprising π-conjugated/π-stacked benzenoid-quinoid donor-acceptor resorcinol units and are active for photocatalytic H2O2 generation. Here, we have prepared phenol-resorcinol-formaldehyde resins with small amounts of phenol (∼5 mol % relative to resorcinol), which show enhanced photocatalytic activity. Incorporating phenol bearing a single -OH group in the resin matrices relaxes the restriction on the arrangement of the aromatic rings originating from the H-bonding interactions between the resorcinol -OH groups. This creates stronger donor-acceptor π-stacking and increases the electron conductivity of the resins. We have demonstrated that simulated sunlight illumination of the resins in water under an atmospheric pressure of O2 stably generated H2O2 with more than 0.9% solar-to-chemical conversion efficiency.

DOI： 10.1021/acsmaterialsau.2c00041

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Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

DOI： 10.1039/d2ce00440b

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/acs.langmuir.2c00336

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

In the long history of zeolite research, further enhancement of their acid strength has looked difficult. In this study, we achieved the enhancement by incorporating Ge into the zeolite framework. We synthesised the zeolites by a dry gel conversion method and characterised them in terms of morphology, crystal structure, and composition. We determined the acid strength of these zeolites by calculating the change in the enthalpy of desorption in the temperature-programmed desorption of ammonia and confirmed that the acid strength of the zeolites with Ge was higher than that of a conventional zeolite. This enhancement of acid strength probably originated from the unprecedented interactions between Al and Ge, unlike the conventional interactions between Al and Si. The enhanced acid strength led to high efficiency of ethanol-to-propylene reactions, affording higher yield of propylene than that obtained using conventional zeolites.

DOI： 10.1002/slct.202200756

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DOI： 10.1021/acsomega.2c00283

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Hydrogen is widely considered an emissions-free alternative energy carrier for sustainable energy devices, such as fuel cells and nickel-metal hydride batteries. Recently, electrochemical hydrogen evolution reaction (HER) from water splitting has been attracted as an eco-friendly process for producing hydrogen. Herein, we report a Co/P-doped carbon material (Co/P/C) derived from cobalt-aluminum layered double hydroxide nanosheets (LDHs) for HER. The Co/P/C was synthesized using triethyl phosphite as phosphate and carbon sources by a one-step chemical vapor deposition (CVD) process. The regular arrangement of Co and Al atoms in the precursor LDHs allowed Co/P species to be highly dispersed under optimized CVD conditions. The carbon nanotube formed by the CVD process improved the catalytic activity of Co/P/C. The optimized Co/P/C exhibits a low overpotential of 240 mV at -10 mA cm-2 for HER, comparable to the commercial Pt/C catalyst. This work provides a new direction for developing transition-metal and hetero-atom co-doped carbon materials with high catalytic activity for HER. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.ijhydene.2022.01.120

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

gamma-Cyclodextrin-based metal-organic framework (CD-MOF) particles were prepared using poor solvent crystallization and spray-drying methods in order to advance conventional engineering processes. Particles were characterized in terms of their morphology, size, surface area, surface elemental composition, crystallinity, and drug content. CD-MOFs prepared by the poor solvent crystallization method exhibit similar morphologies and crystallinities to those fabricated by vapor diffusion. In contrast to the development of the (gamma-CD)(6) cubic array, the rapid evaporation of the solvent during spray-drying promoted the formation of hollow CD-MOF particles with low crystallinity. The CD-MOF structure in spray-dried particles reformed into the well-known (gamma-CD)(6) cubic array following contact with ethanol. In terms of their spherical shape, low density, and geometric median particle size (D-50) that is lower than 5 mu m, the potential application of spray-dried CD-MOF for dry powder inhaler formulation was affirmed. Thus, the spray-drying process was further enhanced using a modified procedure. Modified spray-dried particles achieved an outstanding aerosolization performance by initiating crystal growth using an ethanolic spray-drying precursor. The successful design of this crystal structure grants CD-MOF products a high potential for use in inhalable formulation carriers and likely for other applications in the future.

DOI： 10.1021/acs.cgd.1c01091

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Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

DOI： 10.1039/d1nj05186e

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

UiO-66, composed of a Zr6O4(OH)(4) cluster and 1,4-benzene dicarboxylate, is a promising material for practical chemical processes because it is known as one of the most thermally and chemically stable Metal Organic Frameworks (MOFs). Recently, the structure and composition of UiO-66 have been modified in various ways to improve its functionality and expand its utilization. Herein, we report the synthesis of in situ glycine-modified UiO-66 using a vapor-assisted crystallization (VAC) method. The VAC method using HCl turned out to be the most suitable for synthesizing of glycine-modified UiO-66 with high crystallinity and porosity. Modifying glycine enhanced the CO2 adsorption capacity. In XPS measurement on Zr 3d, the peak shift to higher binding energy was observed by modifying glycine. This result implys that carboxylates derived from glycine chemically interacted with defects of Zr clusters. This work provides a new direction to modify UiO-66.

DOI： 10.1039/d1nj05284e

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.colsurfa.2021.127395

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DOI： 10.4164/sptj.58.497

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society (ACS)  

DOI： 10.1021/jacs.1c04622

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DOI： 10.1016/j.mtchem.2020.100410

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OSDA/solvent-free synthesis of zeolites is suitable for practical commercialization due to low environmental damage and low cost. However, only a few types of zeolites have been successfully synthesized by this method. In this study, ANA, CAN, GIS, SOD, FAU and LTA type zeolites were synthesized by the OSDA/solvent-free synthesis method by changing the Si/Al ratio and crystallization temperature in detail. At higher Si/Al ratios, FAU, GIS and ANA type zeolites were obtained with an increase of crystallization temperature. Meanwhile, at lower Si/Al ratios, LTA, SOD and CAN type zeolites were obtained with an increase of crystallization temperature. It was found that zeolites with high T atom density were synthesized with an increase of the crystallization temperature; zeolite with a high T atomic density is more stable. This work reveals the correlation between the Si / Al ratio and the crystallization temperature in OSDA/solvent-free synthesis of zeolites, which provides a clear guideline for the OSDA/solvent-free synthesis of zeolites.

DOI： 10.1002/ejic.202100049

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Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/app.50251

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/app.50251

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The photocatalytic generation of hydrogen peroxide from water and dioxygen (H O + 1/2O → H O , ΔG° = +117 kJ mol ) under sunlight is a promising strategy for the artificial photosynthesis of a liquid fuel. We had previously found that resorcinol–formaldehyde (RF) resin powders prepared by the base-catalysed high-temperature hydrothermal method act as semiconductor photocatalysts for H O generation. Herein, we report that RF resins prepared by the acid-catalysed high-temperature hydrothermal method (~523 K) using common acids at pH < 4 exhibit enhanced photocatalytic activity. The base- and acid-catalysed methods both produce methylene- and methine-bridged resins consisting of π-conjugated and π-stacked benzenoid–quinoid donor–acceptor resorcinol units. The acidic conditions result in the resins with a lower bandgap (1.7 eV) and higher conductivity because the lower-degree of crosslinking creates a strongly π-stacked architecture. The irradiation of the RF-acid resins with simulated sunlight in water with atmospheric-pressure O generates H O at a solar-to-chemical conversion efficiency of 0.7%, which is the highest efficiency ever reported for powder catalysts used in artificial photosynthesis. 2 2 2 2 2 2 2 2 2 –1

DOI： 10.1038/s42004-020-00421-x

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DOI： 10.1016/j.materresbull.2020.110958

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Fe/N doped porous carbons are promising non-precious electrocatalysts for oxygen reduction reaction (ORR). However, it is still hard to synthesize Fe/N doped porous carbons for ORR. Herein, we present a facile solvent-free method to synthesize Fe/N doped porous carbon as an ideal catalyst for ORR using resorcinol resin, Triblock copolymer Pluronic F127 and iron (II) phthalocyanine (FePc). The Fe/N doped porous carbon has uniform mesopores (ca. 7 nm), highly-dispersed FeN species and FeC nanoparticles. The Fe/N doped porous carbon showed much high onset potential (0.99 V vs. RHE) on ORR owing to the combination of mesoporosity, highly-dispersed FeN species and nanoparticles of Fe and FeC (Fe/FeC NPs). In addition, the limiting current density improved after CO activation. The improvement of the limiting current density was caused by 3-D interconnected hierarchal pore structure. Furthermore, the activated Fe/N doped porous carbon showed high durability and methanol tolerance on ORR. This work revealed the roles of porosity, highly-dispersed FeN species and Fe/FeC NPs on ORR, which provides a clear guideline for the design of Fe/N doped carbon catalysts for ORR. In addition, this facile solvent-free method opens up a new synthesis strategy of transition metal/N doped porous carbons for applications in energy and sustainability. x x x x x 2 x x

DOI： 10.1016/j.mtener.2020.100444

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Recently, NiS based catalysts are promising electrocatalysts for Hydrogen Evolution Reaction (HER) via water electrolysis. In particular, the S/Ni ratio is crucial to improve catalytic activity of NiS based catalysts. Herein, we synthesized NiS based catalysts (Ni/S/C) with a tuned S/Ni molar ratio using Ni ions exchange resin. We succeeded in synthesizing Ni/S/C with different S/Ni molar ratio in the range of 0.33–1.72 by changing Ni ions exchange degree. The combination of NiS and conductive carbon support contributes to high catalytic activity of Ni/S/C on HER. Additionally, Ni/S/C with the S/Ni molar ratio of 0.6 showed the highest onset potential; Ni S is the most active catalyst for HER in NiS species. Our synthesis method can easily tune the ratio of S/transition metal. This work provides a new direction for the catalyst design of transition metal sulfides and expands their utilization in sustainable catalytic reaction processes. x x x x 3 2 x 2+ 2+

DOI： 10.1016/j.ijhydene.2020.06.043

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.mtchem.2019.100209

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

DOI： 10.1021/jacs.0c01683

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Language：English   Publishing type：Research paper (scientific journal)  

The sharp increase in current energy consumption needs the development of fuel cells (FCs) as one of sustainable, renewable, efficient and eco-friendly electrochemical conversion systems of energy. The performance of electrocatalysts is crucially important for commercialization of FCs. Commercial Pt based catalysts are used due to their high catalytic activity. However, widespread commercialization is impossible because of the scarcity and poor durability of Pt based catalysts. We are on our quest to find a more stable and affordable alternative catalyst of Pt based catalysts. In particular, single-atom catalysts supported on graphene are greatly attractive because of their unique characteristic and high catalytic activity. In this work, graphene is hydrothermally treated by sulfuric acid to introduce the ion-exchanging sites. Then, Co ion-exchanging, 2-methylimidazole coordination and pyrolysis process are subsequently conducted to prepare highly-dispersed single-atom Co species catalyst with outstanding ORR activity and durability. This work presents a new direction for a rational design of single-atom catalyst on carbon matrix. 2+

DOI： 10.1002/cnma.201900597

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

DOI： 10.1021/acs.langmuir.9b03445

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

DOI： 10.1021/acsomega.9b02812

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

Zeolites have been applied in various chemical processes due to their multi-functionality. In practical use of zeolites, their hydrothermal stability is one of the important factors. We focused on the coating with hydrophobic silicalite-1, which is all silica MFI zeolite. In this work, we investigated the hydrothermal stability of ZSM-5 (MFI type aluminosilicate zeolite) coated with silicalite-1 (all silica MFI zeolite) by the combination of steam treatment and NH temperature programed desorption (NH -TPD). The peak area at higher temperature (h-peak area) in NH -TPD profiles for core-shell MFI zeolite (ZSM-5/s-1) was unchanged even after steam treatment for 8 h in contrast to uncoated ZSM-5. These results strongly indicate that extremely high Si/Al ratio on the external surface coated with silicalite-1 is highly effective for improving the hydrothermal stability; the hydrophobicity of silicalite-1 probably prevents the penetration of steam into Al sites of ZSM-5. This work opens up a new function of the silicalite-1 layer on ZSM-5 other than improvement of shape selectivity. 3 3 3

DOI： 10.1016/j.micromeso.2019.05.048

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Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media {LLC}  

© 2019, The Author(s), under exclusive licence to Springer Nature Limited. Artificial photosynthesis is a critical challenge in moving towards a sustainable energy future. Photocatalytic generation of hydrogen peroxide from water and dioxygen (H2O + 12O2 → H2O2, ΔG° = 117 kJ mol–1) by sunlight is a promising strategy for artificial photosynthesis because H2O2 is a storable and transportable fuel that can be used directly for electricity generation. All previously reported powder photocatalysts, however, have suffered from low efficiency in H2O2 generation. Here we report that resorcinol–formaldehyde resins, widely used inexpensive polymers, act as efficient semiconductor photocatalysts to provide a new basis for H2O2 generation. Simple high-temperature hydrothermal synthesis (~523 K) produces low-bandgap resorcinol–formaldehyde resins comprising π-conjugated and π-stacked benzenoid–quinoid donor–acceptor resorcinol couples. The resins absorb broad-wavelength light up to 700 nm and catalyse water oxidation and O2 reduction by the photogenerated charges. Simulated sunlight irradiation of the resins stably generates H2O2 with more than 0.5% solar-to-chemical conversion efficiency. Therefore, this metal-free system shows significant potential as a new artificial photosynthesis system.

DOI： 10.1038/s41563-019-0398-0

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

© 2019 American Chemical Society. Au nanoparticles loaded on semiconductor TiO2 absorb visible light due to their surface plasmon resonance (SPR) and inject the photogenerated hot electrons (ehot-) into the conduction band of TiO2. The separated charges promote oxidation and reduction reactions. The step that determines the rate of the plasmonic photocatalysis on the Au/TiO2 system is the ehot- injection through the Schottky barrier created at the Au-TiO2 interface. In the present work, niobium (Nb5+) oxide species were doped at the Au-TiO2 interface by loading Nb5+ onto the TiO2 surface followed by deposition of Au particles (2 wt % of TiO2). Visible light irradiation of the Au/Nb5+/TiO2 catalysts promotes aerobic oxidation of alcohols with much higher efficiency than that of undoped Au/TiO2. Lewis acidity of the Nb5+ species located at the interface cancels the negative charges of Au and creates a barrier with a narrower depletion layer, promoting tunneling ehot- injection. Efficiency of the ehot- injection depends on the amount of Nb5+ doped. Loading small amounts of Nb5+ (0.1 wt % of TiO2) creates mononuclear NbO4 species and shows large activity enhancement. In contrast, loading larger amounts of Nb5+ creates aggregated polynuclear Nb2O5 species. They decrease the electron density of Au particles and weaken their SPR absorption. This suppresses the ehot- generation on the Au particles and decreases the activity of plasmonic photocatalysis.

DOI： 10.1021/acs.langmuir.8b04075

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

An efficient and simple methodology was proposed to synthesize CHA zeolite without the use of solvent and OSDA. The synthesis strategy is based on a mechanochemical-assisted interzeolite transformation using only Na-type FAU zeolite and KOH as starting materials, for ease of handling and large-scale production. The role of KOH on crystal transformation behaviors and adsorption characteristics of the obtained CHA zeolite were investigated. The important factor was the loading KOH into the cages of starting FAU zeolite with adjusted appropriate amount. In this method, vapor-solid interzeolite transformation occurs by local rearrangement of silicon and aluminum species without accompanying macroscopic dissolution of FAU zeolite, resulting in formation of CHA zeolite maintaining the Si/AI ratio of the starting FAU zeolite.

DOI： 10.1016/j.micromeso.2018.11.037

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.poly.2018.11.018

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Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

<p>A simple method was developed to obtain carbon materials with highly dispersed Co/N as electrocatalysts for ORR.</p>

DOI： 10.1039/C8CY02210K

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

Zeolites have been conventionally synthesized using organic structure directing agents (OSDA) in solvent. In this work, we synthesized various zeolites from unseeded aluminosilicate via mechanochemical and vapor treatments in the absence of OSDA and solvent. Various types of zeolites were successfully synthesized from starting materials with different Si/Al ratios. With an increase of Si/Al from 1 to 20, different phases appeared in the order of CAN, ANA, MOR, MFI and α-quartz. This work provides a new insight of zeolite synthesis.

DOI： 10.1016/j.micromeso.2018.06.044

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry ({RSC})  

Propane dehydrogenation (PDH) is one of the most promising candidates for the propylene production process to meet the growing demand of propylene for the future. There is an urgent need to develop catalysts for PDH. In this work, we have synthesized high silica Ga-Beta as a new candidate for a catalyst from dealuminated zeolite using the dry gel conversion method. A high silica Ga-Beta catalyst with a Si/Ga ratio of up to 177 can be synthesized. In the PDH reaction, the synthesized Ga-Beta showed the highest propane conversion and the highest propylene yield amongst the Ga-based zeolites. The combination of the Ga species being incorporated into zeolite frameworks, its large microporosity and Bronsted acidity is likely to lead to the excellent catalytic performance of Ga-Beta. Moreover, Ga-Beta with a higher Si/Ga ratio shows a longer catalyst lifetime for the PDH reaction, since the coke deposition rate decreased with the decrease in the amount of acid. This work provides new insights for the PDH reaction over Ga-based zeolite catalysts, and contributes to the progress in the activation and transformation of light alkenes to value-added chemicals.

DOI： 10.1039/C9CY00691E

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Development of electrocatalysts for oxygen reduction reaction (ORR) is important to solve the current problems about energy and fuel. As one of the catalysts with high performance, platina group metals (PGM) based catalysts have been widely known. However, PGM based catalysts are not suitable for large commercial application since the PGM based catalysts are so expensive. In this work, we have developed TiO P25 coated with Co and nitrogen-doped carbon layers using commercially available and inexpensive P25 as a support (Co/P25/NC) as one of the alternatives to PGM based catalysts. Co/P25/NC showed an excellent catalytic activity on ORR compared to the other catalysts prepared using SiO , ZrO and Al O as a support. The ORR activity of Co/P25/NC was comparable to Pt based electrocatalysts. In addition, Co/P25/NC showed excellent durability and tolerance toward methanol compared to the Pt based catalyst. This work would provide a new synthetic strategy of electrocatalysts. 2 2 2 2 3

DOI： 10.1016/j.electacta.2018.11.080

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Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

© Copyright 2018 American Chemical Society. Ammonia (NH3), which is an indispensable chemical, is produced by the Haber-Bosch process using H2 and N2 under severe reaction conditions. Although photocatalytic N2 fixation with water under ambient conditions is ideal, all previously reported catalysts show low efficiency. Here, we report that a metal-free organic semiconductor could provide a new basis for photocatalytic N2 fixation. We show that phosphorus-doped carbon nitride containing surface nitrogen vacancies (PCN-V), prepared by simple thermal condensation of the precursors under H2, produces NH3 from N2 with water under visible light irradiation. The doped P atoms promote water oxidation by the photoformed valence-band holes, and the N vacancies promote N2 reduction by the conduction-band electrons. These phenomena facilitate efficient N2 fixation with a solar-to-chemical conversion (SCC) efficiency of 0.1%, which is comparable to the average solar-to-biomass conversion efficiency of natural photosynthesis by typical plants. Thus, this metal-free catalyst shows considerable potential as a new method of artificial photosynthesis.

DOI： 10.1021/acsaem.8b00829

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

An efficient and simple mechanosynthesis was proposed to synthesize zeolitic imidazolate-based metal organic framework ZIF-8 with hierarchical superstructure. The synthesis strategy is based on a concept that only uses precursor powders for ease of handling in the solid-solid mechanochemical reaction. The solvent-free conversion of ZnO to ZIF-8 could be accelerated by an addition of zinc acetate dihydrate as both a Zn source and a catalyst. The acid dissolution of ZnO and complex forming reaction between ionized Zn and 2-methylimidazole were facilitated by the hydrated water and acetic acid generated sequentially from zinc acetate dihydrate during the reaction process. The mechanochemically synthesized ZIF-8 with trimodal hierarchical porous structure exhibited excellent adsorption rate capabilities. The large-scale rapid production and enhanced adsorption performances make this salt-assisted mechanosynthesis a very promising candidate for the industrial application and shaping of metal organic frameworks.

DOI： 10.1021/acs.cgd.7b01211

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

In this work, a dual-functional catalyst with (1) catalytic activity of metal catalysts and (2) shape-selectivity of zeolites has been developed. We have fabricated Pt nanoparticles encapsulated in core-shell single crystal like silicalite-1 zeolite (CS-Pt/s-1) by a crystalline overgrowth method. The CS-Pt/s-1 catalyst showed much higher catalytic hydrogenation activity of n-hexene compared to cyclohexene.

DOI： 10.1016/j.micromeso.2018.05.051

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley Blackwell  

Photocatalytic production of hydrogen peroxide (H2O2) from earth-abundant water and O2 is a desirable artificial photosynthesis for solar fuel production. A metal-free hybrid photocatalyst consisting of pyromellitic diimide-doped carbon nitride (g-C3N4/PDI), boron nitride (BN), and reduced graphene oxide (rGO) was prepared. The g-C3N4/PDI-BN-rGO catalyst, when photoirradiated in water with O2 by visible light at room temperature, efficiently produces H2O2. The photoexcited g-C3N4/PDI moiety transfers the conduction band electrons to rGO, leading to selective production of H2O2 via two-electron reduction of O2 on the rGO surface. In contrast, the valence-band holes photoformed on the g-C3N4/PDI moieties are transferred to BN, leading to efficient oxidation of water. The electron–hole separation enhanced by the incorporation of rGO and BN significantly suppresses the charge recombination and exhibits high photocatalytic activity. The solar-to-chemical conversion (SCC) efficiency for H2O2 production on the hybrid catalyst is 0.27 %, which is higher than the highest efficiencies obtained by overall water splitting on powdered catalysts.

DOI： 10.1002/cctc.201701683

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

ZIF-8 metal organic framework "micrometer-thick" films were constructed from ZnO precursor by a vapor-phase synthesis. The ZnO-to-ZIF-8 crystal transformation proceeded in the presence of 2-methylimidazole (Hmim) vapor. Continuous coatings of intergrown ZIF-8 crystals require control of a nucleation density. The dependence of ZnO crystal plane on the ZnO-to-ZIF-8 crystal transformation was investigated using four bulk ZnO single crystals: a-plane (11-20), c-plane (0001), m-plane (10-10), and r-plane (10-11). It was revealed that the m-plane (10-10) of ZnO is more effectively transformed into ZIF-8. In this work, highly oriented ZnO nanorod array film was used to provide the transport pathway of Hmim molecules and volume expansion space of ZnO-to-ZIF-8 crystal transformation for nucleation and crystal intergrowth. The high conversion of ZnO nanorod array into ZIF-8 in a short time could be achieved because (1) such mass transfer is easy due to the uniform internanorod distance being maintained during reaction and (2) the surface of the nanorod array is dominated by the highly reactive m-plane (10-10).

DOI： 10.1021/acs.langmuir.8b00948

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Partial oxidation of cyclohexane (CHA) to cyclohexanone (CHA-one) with molecular oxygen (O-2) is one of the most important reactions. Photocatalytic oxidation has been studied extensively with TiO2-based catalysts. Their CHA-one selectivities are, however, insufficient because the formed CHA-one is subsequently decomposed by photo catalysis involving the reaction with superoxide anion (O-2(center dot-)) produced by one-electron reduction of O-2 on TiO2. Here we report that TiO2, when hybridized with reduced graphene oxide (rGO), catalyzes photooxidation of CHA to CHA-one with enhanced activity and selectivity under UV light (A &gt; 300 nm). The TiO2/rGO hybrids produce CHA-one with twice the amount formed on bare TiO2 with much higher selectivity (&gt;80%) than that on bare TiO2 (ca. 60%). The conduction band electrons photoformed on TiO2 are transferred to rGO, promoting efficient charge separation and enhanced photocatalytic cycles. The trapped electrons on rGO selectively promote two-electron reduction of O-2 and suppress one-electron reduction. This inhibits the formation of O-2(center dot-), which promotes photocatalytic decomposition of the CHA-one formed. These properties of rGO therefore facilitate efficient and selective formation of CHA-one on the hybrid catalyst.

DOI： 10.1021/acscatal.6b02611

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Dehalogenation of aromatic halides is one important reaction for detoxification and organic synthesis. Photocatalytic dehalogenation with alcohol, a safe hydrogen source, is one promising method; however, systems reported earlier need UV irradiation. We found that Pt-Pd bimetallic alloy nanoparticles (ca. 4 nm) supported on Ta2O5 (PtPd/Ta2O5), on absorption of visible light (lambda &gt; 450 nm), efficiently promote dehalogenation with 2-PrOH as a hydrogen source. Catalytic dehydrogenation of 2-PrOH on the alloy in the dark produces hydrogen atoms (H) on the particles. Photoexcitation of d electrons on the alloy particles by absorbing visible light produces hot electrons (e(ho)t(-)). They efficiently reduce the adsorbed, H atoms and produce hydride species (H-) active for dehalogenation. The catalytic activity depends on the Pt/Pd mole ratio; alloy particles consisting of 70 mol % of Pt and 30 mol % of Pd exhibit the highest activity for dehalogenation.

DOI： 10.1021/acscatal.7b01735

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Polycrystalline ZIF-8 membranes of about 1 mu m in thickness were successfully grown on alpha-alumina porous support by seeding-free aqueous synthesis. In order to achieve continuous well-intergrown membranes, a pseudo-surface of ZIF-8 was formed on the support by chemical modification. Our membrane preparation in aqueous system is based on the support-surface activation concept to control the surface density of nucleation sites. The grain size of polycrystalline membrane is directly related to a graft density of ligand-analogous surface modifier. Single-component gas permeation properties were investigated using H-2, CO2, N-2, CH4, C3H6, and C3H8. While the ideal permselectivities of H-2 from CO2, N-2, CH4, and C3H6 ever so slightly increased with the graft density, the ideal permselectivity of C3H6/C3H8 increased rapidly and reached 36 with corresponding C3H6 permeance of 8.5 x 10(-8) mol/m(2) s Pa. As a conclusion of the combined characterization with adsorption analysis, it was found that the sieving of C3H6/C3H8 by our seeding-free aqueous-synthesized ZIF-8 membrane is mainly governed by diffusion-driven separation process.

DOI： 10.1016/j.memsci.2017.09.037

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Visible light absorption of plasmonic Au nanoparticles supported on semiconductor TiO2 leads to injection of their photoactivated "hot electrons (e(hot)(-))" into the TiO2 conduction band. This charge separation facilitates several oxidation and reduction reactions. These plasmonic systems, however, suffer from low quantum yields because the Schottky barrier created at the Au-TiO2 interface suppresses e(hot)(-) injection. Here we report that Au nanoparticles supported on the anatase particles isolated from Degussa (Evonik) P25 TiO2 promote e(hot)(-) injection with much higher efficiency than those supported on other commercially-available TiO2 and catalyze aerobic oxidation with very high quantum yield (7.7% at 550 nm). Photoelectrochemical and spectroscopic analysis revealed that the number of Ti4+ atoms located at the Au-TiO2 interface is the crucial factor. These Ti4+ atoms neutralize the negative charge of the Au particles and create a Schottky barrier with narrower depletion layer. This facilitates efficient e(hot)(-) injection by "quantum tunneling" through the Schottky barrier without overbarrier energy. The e(hot)(-) injection depends on several factors, and loading of 2 wt% Au particles with 3.5-4 nm diameters at around room temperature exhibits the highest activity of plasmonic photocatalysis.

DOI： 10.1039/c7nr02310c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Generating hydrogen peroxide (H2O2) from water and dioxygen (O-2) by photocatalysis is one ideal artificial photosynthesis for solar fuel production. Several early reported powdered photocatalysts, however, produce small amounts of H2O2 (&lt;0.1 mM). We prepared graphitic carbon nitride (g-C3N4) doped with mellitic triimide (MTI) units by thermal condensation of melem and mellitic acid anhydride. The g-C3N4/MTI photocatalyst, when irradiated by visible light (lambda &gt; 420 nm) in pure water with O-2, successfully produces millimolar levels of H2O2 via water oxidation by valence band holes and selective two-electron reduction of O-2 by conduction band electrons. The incorporation of triply branched MTI units creates a condensed melem layer. This facilitates efficient intra- and interlayer transfer of photogenerated charge carriers and shows high electrical conductivity. The solar-to-chemical conversion efficiency for H2O2 production on the catalyst is 0.18%, which is higher than that of natural photosynthesis (similar to 0.1%) and similar to the highest values obtained by semiconductor water-splitting catalysts.

DOI： 10.1021/acssuschemeng.7b00575

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Zeolites have been widely applied as sophisticated solid acid catalysts in chemical industries. Tuning the acidic properties of zeolites is very important to improve their catalytic performances and expand their utilization. Herein, we synthesized AEI-type Ge-incorporated aluminophosphate, GeAPO-18, by a dry gel conversion method in order to generate new acidity. GeAPO-18 had weaker Bronsted acid sites than the conventional SAPO-18. To confirm the effect of the substitution of Ge, we carried out the methanol to olefin (MTO) reaction over GeAPO-18 and the conventional SAPO-18. The catalyst lifetime of GeAPO-18 in the MTO reaction was longer than that over the conventional SAPO-18. The rate of coke deposition on GeAPO-18 was slower than that on the conventional SAPO-18. These results indicated that the decreased acid strength of GeAPO-18 could retard the coke formation via undesired successive reactions. The incorporation of Ge into the aluminophosphate zeolite framework was a crucial method for tuning the acid strength, which provides a new direction for the design of solid acid catalysts.

DOI： 10.1039/c7cy01153a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society ({ACS})  

Zeolitic imidazolate framework-8 shares the same topology with sodalite zeolite but consists of Zn nodes bridged by imidazolate linkers to form a neutral openframework structure. ZIF-8 has been recognized as a unique molecular sieving material with a flexible framework enabling interesting "gate-opening" functionality. Controlling the crystal size and shape is crucial for regulating the structural flexibilities and mass transport properties. The present study demonstrates that an aqueous-system-enabled spray-drying process enables the shape engineering of ZIF-8 with a hollow polycrystalline structure. It is notable that our synthesis route produces an amorphous zinc complex compound, which possesses a continuous random network partially with crystalline fillers, after spray drying followed by an amorphous-to-crystal transition via activation treatment using polar organic solvents. The size of primary ZIF-8 crystals consisting of secondary polycrystals depends on the kind of the organic solvent. The macro-/microscopic structures of hollow polycrystalline ZIF-8 significantly structurally enhanced the adsorption capacity and uptake rate. The largescale, rapid production and enhanced adsorption performances make this continuous method a very promising candidate for industrial applications and shaping of MOF.

DOI： 10.1021/acsomega.7b01325

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Various synthesis methods of zeolites have been established. Hydrothermal synthesis method with organic structure directing agent (OSDA) has been widely applied in zeolite synthesis. However, this method has some big problems in terms of industrial and environmental aspects: OSDA is expensive and thermally decomposed OSDA produces air pollution; and the yield of zeolite crystals per reactor volume is low due to the presence of solvent. We hence synthesized ZSM-5 (MFI-type zeolite) in the absence of both solvent and OSDA to overcome these problems. Briefly, the starting materials including silica powder, sodium aluminate, sodium hydroxide and a small amount of seed crystals (ZSM-5) were mixed together and grinded using a ball mill. Then the milled powder was crystallized under a steam atmosphere by varying crystallization time. We found that an MFI phase started to appear after 12h and the formation of pure ZSM-5 crystals was completed after 24h. Our method provides a simpler and efficient process of zeolite synthesis in an environment-friendly manner than those of any conventional solvent methods, which will promise to promote mass production of a variety of zeolites.

DOI： 10.1002/slct.201701593

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

A facile solvothermal method is developed to synthesize N-doped 3D bicontinuous macro/mesoporous carbon through co-gelation of in-situ polymerized N-enriched resin together with in-situ formed colloidal silica packing domains. The resultant material possesses abundant pyridinic/graphitic N, respectable surface area, and smooth pore channels (interconnected macropores with open mesopores ca. 16 nm). Due to the combined contributions of above features, it shows high oxygen reduction catalytic activity with excellent durability and tolerance to methanol crossover effect. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elecom.2016.12.006

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

We successfully designed Zn ion doped ZSM-5/silicalite-1 core-shell zeolite catalyst. On methanol to para-xylene (MTpX) over the core-shell catalyst, p-xylene yield was 40.7 C-mol% and para-selectivity (para-xylene selectivity in xylene isomers) was higher than 99 C-mol%, which substantially exceeds the other results reported in the literature. (C) 2016 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jcat.2016.07.008

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Solar-to-chemical energy conversion is a challenging subject for renewable energy storage. In the past 40 years, overall water splitting into H-2 and O-2 by semiconductor photocatalysis has been studied extensively; however, they need noble metals and extreme care to avoid explosion of the mixed gases. Here we report that generating hydrogen peroxide (H2O2) from water and O-2 by organic semiconductor photocatalysts could provide a new basis for clean energy storage without metal and explosion risk. We found that carbon nitride aromatic diimide graphene nanohybrids prepared by simple hydrothermal calcination procedure produce H2O2 from pure water and O-2 under visible light (lambda &gt; 420 nm). Photoexcitation of the semiconducting carbon nitride aromatic diimide moiety transfers their conduction band electrons to graphene and enhances charge separation. The valence band holes on the semiconducting moiety oxidize water, while the electrons on the graphene moiety promote selective two-electron reduction of O-2. This metal-free system produces H2O2 with solar-to-chemical energy conversion efficiency 0.20%, comparable to the highest levels achieved by powdered water-splitting photocatalysts.

DOI： 10.1021/jacs.6b05806

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Photocatalytic hydrogen peroxide (H2O2) production from water and molecular oxygen (O2) by sunlight is a promising strategy for green, safe, and sustainable H2O2 synthesis. We prepared graphitic carbon nitride (g-C3N4) doped with electron-deficient biphenyl diimide (BDI) units by a simple calcination procedure. The g-C3N4/BDI catalyst, when photoirradiated by visible light (λ &gt
420 nm) in pure water with O2, successfully promotes water oxidation by the photogenerated valence band holes and selective two-electron reduction of O2 by the conduction band electrons, resulting in successful production of millimolar levels of H2O2. Electrochemical analysis, Raman spectroscopy, and ab initio calculation results revealed that, upon photoexcitation of the catalyst, the photogenerated positive holes are localized on the BDI unit while the conduction band electrons are localized on the melem unit. This spatial charge separation suppresses rapid recombination of the hole-electron pairs and facilitates efficient H2O2 production. The solar-to-chemical energy conversion efficiency for H2O2 production is 0.13%, which is comparable to that for photosynthetic plants. This metal-free photocatalysis therefore shows potential as an artificial photosynthesis for clean solar fuel production.

DOI： 10.1021/acscatal.6b02367

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Pure lithium titanate (Li4Ti5O12) nanoparticles were synthesized at low temperature via a new simple method. First, amorphous titanium dioxide (TiO2) nanoparticles with a high surface area (624 m(2) g(-1)) were prepared by using tetrahydrofuran (THF) as a solvent in the hydrolysis reaction of titanium tetraisopropoxide (TTIP) at room temperature. Pure Li(4)T(i)5O(12) nanoparticles with a particle size of 10-30 nm were obtained by introducing Li+ into the amorphous TiO2 nanoparticles at room temperature.

DOI： 10.1246/cl.160702

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Photocatalytic production of hydrogen peroxide (H2O2) from ethanol (EtOH) and molecular oxygen (O-2) was carried out by visible light irradiation (lambda &gt; 420 nm) of mesoporous graphitic carbon nitride (GCN) catalysts with different surface areas prepared by silica-templated thermal polymerization of cyanamide. On these catalysts, the photoformed positive hole oxidize EtOH and the conduction band electrons localized at the 1,4-positions of the melem unit promote two-electron reduction of O-2 (H2O2 formation). The GCN catalysts with 56 and 160 m(2) g(-1) surface areas exhibit higher activity for H2O2 production than the catalyst prepared without silica template (surface area: 10 m(2) g(-1)), but a further increase in the surface area (228 m(2) g(-1)) decreases the activity. In addition, the selectivity for H2O2 formation significantly decreases The mesoporous GCN with larger surface areas inherently contain a larger number of primary amine moieties at the surface mesopores. These defects behave as the active sites for four-electron reduction of O-2, thus decreasing the H2O2 selectivity. Furthermore, these defects also behave as the active sites for photocatalytic decomposition of the formed H2O2. Consequently, the GCN catalysts with relatively large surface area but with a small number of surface defects promote relatively efficient H2O2 formation.

DOI： 10.1021/acscatal.5b00408

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

The increasing demand for energy has triggered numerous research efforts for the development of electricity storage devices consisting of templated nanoporous carbons. In this study, ordered mesoporous carbon with a modest specific surface area (520 m(2)/g) was prepared by a soft-templating method and surface-modified by a wet oxidation using nitric acid and ammonium peroxodisulfate. More oxygen-containing functional groups were introduced on the surface by oxidation using ammonium peroxodisulfate rather than nitric acid. Our study systematically investigates the effect of surface modification on electrochemical performance, based on comparisons with oxidized commercial activated microporous carbons. Oxygen functionalization leads to an increased capacitance for the ordered mesoporous carbon and a decreased capacitance for the activated microporous carbon at higher power densities. The ordered mesoporous carbon oxidized by nitric acid demonstrates excellent electrochemical performance with gravimetric capacitance of 290 F/g and volumetric capacitance of 300 F/cm(3) at 0.1 A/g and retains over 70% of the capacitance at high current density of 5 A/g even though its surface area remained moderate (430 m(2)/g). The device demonstrates remarkable performance with an energy density of 17.4 Wh/kg, power density of 5.2 kW/kg, and excellent cycle life. (C) 2015 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.micromeso.2015.06.017

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Photoirradiation (lambda &gt; 300 nm) of Degussa (Evonik) P25 TiO2, a mixture of anatase and rutile particles, in alcohols containing nitroaromatics at room temperature produces the corresponding imines with very high yields (8096%). Other commercially available anatase or rutile TiO2 particles, however, exhibit very low yields (&lt;30%). The imine formation involves two step reactions on the TiO2 surface: (i) photocatalytic oxidation of alcohols (aldehyde formation) and reduction of nitrobenzene (aniline formation) and (ii) condensation of the formed aldehyde and aniline on the Lewis acid sites (imine formation). The respective anatase and rutile particles were isolated from P25 TiO2 by the H2O2/NH3 and HF treatments to clarify the activity of these two step reactions. Photocatalysis experiments revealed that the active sites for photocatalytic reactions on P25 TiO2 are the rutile particles, promoting efficient reduction of nitrobenzene on the surface defects. In contrast, catalysis experiments showed that the anatase particles isolated from P25 TiO2 exhibit very high activity for condensation of aldehyde and aniline, because the number of Lewis acid sites on the particles (73 mu mol g(1)) is much higher than that of other commercially available anatase or rutile particles (&lt;15 mu mol g(1)). The P25 TiO2 particles therefore successfully promote tandem photocatalytic and catalytic reactions on the respective rutile and anatase particles, thus producing imines with very high yields.

DOI： 10.1021/am508769x

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Photoexcitation (lambda &gt; 300 nm) of TiO2 loaded with Pt particles promotes selective hydrogenolysis of epoxides using alcohols as reducing agents.

DOI： 10.1039/c4cc09307k

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Aerobic oxidation on a heterogeneous catalyst driven by visible light (lambda &gt;400 nm) at ambient temperature is a very important reaction for green organic synthesis. A metal particles/semiconductor system, driven by charge separation via an injection of "hot electrons (e(hot)(-))" from photoactivated metal particles to semiconductor, is one of the promising systems. These systems, however, suffer from low quantum yields for the reaction (&lt;5% at 550 nm) because the Schottky barrier created at the metal/semiconductor interface suppresses the e(hot)(-) injection. Some metal particle systems promote aerobic oxidation via a non-e(hot)(-)-injection mechanism, but require high reaction temperatures (&gt;373 K). Here we report that Pt nanoparticles (similar to 5 nm diameter), when supported on semiconductor Ta2O5, promote the reaction without e(hot)(-) injection at room temperature with significantly high quantum yields (similar to 25%). Strong Pt-Ta2O5 interaction increases the electron density of the Pt particles and enhances interband transition of Pt electrons by absorbing visible light. A large number of photogenerated e(hot)(-) directly activate O-2 on the Pt surface and produce active oxygen species, thus promoting highly efficient aerobic oxidation at room temperature.

DOI： 10.1021/jacs.5b04062

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

ZIF-8 is a flexible zeolitic imidazole-based metal organic framework whose narrow pore apertures swing open by reorientation of imidazolate linkers and expand when probed with guest molecules. This work reports on the crystal size dependency of both structural transitions induced by N-2 and Ar adsorption and dynamic adsorption behavior of n-butanol using well-engineered ZIF-8 crystals with identical surface area and micropore volume. It is found that the crystal downsizing of ZIP-8 regulates the structural flexibility in equilibrium adsorption and desorption of N-2 and Ar. Adsorption kinetics of n-butanol in ZIF-8 are strongly affected by the crystal size, however, not according to a, classical intracrystalline diffusion, mechanism. Our results suggest that Structural transitions and transport properties are dominated by crystal surface effects. Crystal downsizing increases the importance of such surface barriers.

DOI： 10.1021/acs.jpcc.5b09520

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Platinum (Pt) nanoparticles with &lt;4 nm diameter loaded on graphitic carbon nitride (g-C3N4) by reduction at 673 K behave as efficient co-catalysts for photocatalytic hydrogen evolution under visible light (lambda &gt; 420 nm). This is achieved by strong Pt-support interaction due to the high temperature treatment, which facilitates efficient transfer of photoformed conduction band electrons on g-C3N4 to Pt particles.

DOI： 10.1039/c4cc06960a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

Design of green, safe, and sustainable process for the synthesis of hydrogen peroxide (H2O2) is a very important subject. Early reported processes, however, require hydrogen (H-2) and palladium-based catalysts. Herein we propose a photocatalytic process for H2O2 synthesis driven by metal-free catalysts with earth-abundant water and molecular oxygen (O-2) as resources under sunlight irradiation (lambda &gt; 400 nm). We use graphitic carbon nitride (g-C3N4) containing electron-deficient aromatic diimide units as catalysts. Incorporating the diimide units positively shifts the valence-band potential of the catalysts, while maintaining sufficient conduction-band potential for O-2 reduction. Visible light irradiation of the catalysts in pure water with O-2 successfully produces H2O2 by oxidation of water by the photoformed valence-band holes and selective two-electron reduction of O-2 by the conduction band electrons.

DOI： 10.1002/anie.201407938

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Zeolitic imidazolate frameworks (ZIFs) have received attention for membrane separation applications due to their zeolite-like permanent porosity and tunable uniformly sized micropores. Although aqueous room temperature synthesis has apparently opened up environmental friendly and efficient ways to synthesize ZIFs, it poses challenges for membrane preparation including unavoidable homogeneous nucleation. Many ZIF membranes prepared in an aqueous system are based On conventional secondary seeded growth techniques for zeolite membranes in spite of well-recognizing that the coordination chemistry of ZIFs is fundamentally different from the covalent chemistry of zeolites. In this study, we first applied a support-surface activation approach to promote heterogeneous nucleation followed by crystal growth in the aqueous system. Continuous well-intergrown ZIF-8 membranes were successfully grown on alpha-alumina porous support using zinc acetate and showed relatively-high hydrogen permeance of 6.9 x 10(-7) mol/m(2) s Pa with corresponding ideal separation selectivity of 13.6 for the hydrogen/methane. The competitive interaction between the coordination of constructing framework and zinc-acetate interaction by carboxylate functionality of acetate anions is essential to control heterogeneous nucleation and membrane growth. Avoiding the seeding process and reducing the use of organic solvents can provide potential for improving a reproducible, scalable, and commercializable process configuration for membrane preparation. (C) 2014 Elsevier B.V. All rights reserved,

DOI： 10.1016/j.memsci.2014.08.038

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© 2013 by Taylor &amp; Francis Group, LLC. There has been a growing interest in new applications of porous carbons because of their chemical inertness, conductive property, high surface area, and mechanical resistance. Porous carbon materials have been applied in various applications, including gas separation, water purification, catalyst supports, and electrodes for batteries and fuel cells. Different pore size distributions are applied in different practical fields. Especially, the development of mesopores is of great importance because it allows the carbon materials to adsorb large molecules such as polymers, dyes, or vitamins. The importance of mesopores has been pointed out not only for giant molecule adsorption but also for new applications, such as electric double-layer capacitors. The recent development of industrial technology providing new application fields for porous carbons requires the porous carbons to have a desired pore structure. To meet such requirements, novel approaches to control the pore structure of carbons are very important.

DOI： 10.1201/b13784

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

The synthesis of zeolitic imidazolate framework-8 (ZIF-8) films in an aqueous system was achieved. ZIF-8 films with controllable thickness were successfully grown on a modified substrate at room temperature. The 3-(2-imidazolin-1-yl)propyltriethoxysilane (IPTES) was used to first form a pseudo-surface of ZIF-8 on a glass substrate, followed by layer-by-layer growth. The film thickness of ZIF-8 was controlled within the range from 220 to 640 nm per growth cycle by changing the reactivity of the zinc source. Notably, the use of a preorganized zinc source led to drastic changes in the formation rate of ZIF-8. The use of a low-reactivity growth solution containing zinc acetate thus allowed the preparation of dense ZIF-8 films.

DOI： 10.1039/c3dt51135a

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

DOI： 10.1002/anie.201302430

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-V C H VERLAG GMBH  

DOI： 10.1002/anie.201301669

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Mechanochemical dry conversion that only uses zinc oxide and an imidazole ligand proved to be effective and reliable for fabrication of a zeolitic imidazolate framework with a polycrystalline grain boundary and a core-shell structure. The zinc oxide crystals are converted into a zeolitic imidazolate framework to a depth of approx. 10 nm below the surface.

DOI： 10.1039/c3cc43028f

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A membrane reactor (MR) for the water gas shift (WGS) reaction was developed by integrating a highly hydrogen permselective silica membrane. The membrane was prepared using an extended counter-diffusion chemical vapor deposition (CVD) method. A tetramethylorthosilicate (TMOS) silica source was fed from one side of the membrane support and oxygen gas fed from the other. The dense silica film was deposited on a porous support by pressurizing the side that TMOS is supplied. A high hydrogen permselective silica membrane was obtained by this method. A commercial Pt catalyst was used in the WGS reaction. Efficacy of the silica membrane toward the WGS reaction was investigated as a function of temperature (523-623 K), steam/carbon monoxide (S/C) ratio (1-3), differential pressure (0-100 kPa), and gas hourly space velocity (GHSV
1800-5400 h-1). The CO conversion in the MR was higher than that for a fixed bed reactor (FBR) under all experimental conditions, and was also higher than the thermodynamic equilibrium conversion under almost all experimental conditions. This was due to the selective abstraction of hydrogen from the product stream by the silica membrane. At an S/C of 1.0, the CO conversion in the MR was superior to that in a FBR by 16.8%. © 2013 Copyright Taylor and Francis Group, LLC.

DOI： 10.1080/01496395.2012.674602

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Mesoporous carbons were synthesized by organic-organic self-assembly of triblock copolymer F127 and phenolic resin oligomers composed of resorcinol-formaldehyde or resorcinol-furfural. The mesostructure control was performed by using different polymerization catalysts, ammonia and acetic acid. The effects of the aldehyde and polymerization catalyst on pore architecture of mesoporous carbons were investigated. Disordered mesostructure with poorly disconnected mesopores was formed using furfural. In contrast, when formaldehyde was used, ordered structure with mesochannels was formed. In addition, changes in mesochannel length and the degree of long-range order are found to depend on polymerization catalyst. The porous carbons with different structure were used as a model material to investigate the ion storage/transfer behavior in electrical double-layer capacitor. Electrochemical cyclic voltammetry measurements were conducted in 1 M sulfuric acid electrolyte solution. The ordered mesoporous carbons show superior capacitances and rate performance over the disordered carbons. Electrochemical impedance spectroscopy was used to assess the transport properties. The impedance data clearly demonstrated that the degree of long-range order and channel length can influence the ion transport, resulting in superior capacitive performances. (C) 2013 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

DOI： 10.1016/j.apt.2013.03.003

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We report here the synthesis of a zeolitic imidazolate framework-8 (ZIF-8) in an aqueous solution. ZIF-8 crystals were prepared by mixing 2-methylimidazole (Hmim) with Zn nitrate hexahydrate (Zn) in deionized water. The products prepared at high Hmim/Zn molar ratios were assigned to a sodalite (SOD)-type structure whose morphology consisted of a rhombic dodecahedron with truncated corners. The crystals possessed ultrahigh surface areas and micropore volumes. At low Hmim/Zn molar ratio, some zinc hydroxide and basic zinc nitrate were observed in the products. We also focused on the formation process of ZIF-8 crystals in an aqueous system by observing the change in the pH value as a function of synthesis time. We tried to calculate the stability constant of ZIF-8 by fitting the calculated pH values to the measured pH values. When the molar fractions of the zinc compounds in the equilibrium state were calculated, high fractions of the Zn(mim)(2) complex were observed at high concentrations of Hmim. On the other hand, some zinc cations were present at low concentrations of Hmim. This finding would support a causal relationship between these zinc cations and the formation of some by-products.

DOI： 10.1039/c2ce26847g

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Ordered mesoporous carbons have attracted great interest for their potential use to electrodes for electric double layer capacitors. However, it is crucial to develop an electrode such that the active sites within the mesoporous carbons are accessible to electrolyte solution species via facile mass transport through well-defined pores. Here, we investigate the electrolyte accessibility and the effective mass transport for the ordered mesoporous carbons possessing p6mm symmetry, whereas having different mesochannel length, formed by soft-templating self-assembly. Mesoporous carbons were prepared from a thermosetting phenolic resin and a thermally decomposable copolymer template in ethanol/water solutions of different molar ratios. The general evolution of the mesophase follows the trends that are expected based on packing parameters due to swelling of the hydrophobic volume of the copolymer micelles. However, changes in mesochannel length and the degree of long-range order are found to depend on ethanol/water ratio. Electrochemical impedance spectroscopy was used to assess the transport properties. The impedance data clearly demonstrated that the degree of long-range order and channel length can be a dominant factor that determines the transport and the degree to which the equilibrium adsorption sites are accessible. The lengthy mesochannels in well-ordered mesoporous carbon serve as ion-highways and allow for very fast mass transport into the micropores of the channel frameworks. (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jpowsour.2012.11.114

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Language：English   Publishing type：Research paper (scientific journal)  

There is no universally accepted theoretical interpretation of the rate constant of the pseudo-second order kinetic model of adsorption. This study proposes a relationship for the rate constant of the pseudo-second order adsorption model based on the diffusion mass transfer of the adsorbate within spherical homogeneous adsorbent microspheres. This relationship provides a new interpretation of the physical meaning of the rate constant mentioned above.A detailed study of the adsorption of Ag(I) onto and within isolated mesoporous silica microspheres functionalized with thiol groups has been conducted. The experimental data were fitted successfully by the pseudo-second order model resulting in the determination of the values of the corresponding apparent diffusion coefficient (DAg) and the adsorbate adsorbed on the surface of the particles (qs). The latter value was found to be almost equal to the corresponding equilibrium value (qe). The logarithm of the value of DAg increased linearly from 2.5×10-17m2/s to 6×10-16m2/s with the decrease in the saturation ratio (qs/qmax where qmax is the maximum amount of Ag adsorbed). © 2012 Elsevier B.V..

DOI： 10.1016/j.cej.2012.11.089

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Highly ordered mesoporous silicoaluminophosphates were synthesized using LTA zeolite dissolved acidic solutions. In the first step, zeolite nanoblocks are prepared from zeolite crystals by dissolution of LTA in an H3PO4/HCl solution of carefully controlled concentration. In the second step, we combine the above solution and PEO106PPO70PEO106 triblock copolymer aqueous solution to carry out the self-assembly process. Dealumination from the zeolite framework occurs in the first step, but the zeolite nanoblocks still retain the local structure of the Si-O-Al bonding. In addition, the incorporation of phosphorus species in the framework inhibits the release of aluminum species. (C) 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.matlet.2012.10.108

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Zeolite rho was prepared by hydrothermal synthesis using an 18-crown-6 ether (18C6) as a structure-directing agent, and the effects of the calcination temperature for removal of 18C6 on the physicochemical properties and CO2-adsorption properties were investigated. CO2 adsorption on zeolite rho calcined at 150 degrees C was lower than that on samples calcined at temperatures above 300 degrees C. For samples calcined above 300 degrees C, CO2 adsorption increased with increasing calcination temperature up to 400 degrees C. It is thought that the pore volume for adsorption of CO2 increased as a result of 18C6 removal, resulting in increasing CO2 adsorption. A decrease in CO2 adsorption for calcination from 400 degrees C to 500 degrees C was observed. The particle size of zeolite rho increased with increasing 18C6 molar ratio. Particle sizes of 1.0-2.1 mu m and 1.4-2.6 mu m were found by field-emission scanning electron microscopy and dynamic light-scattering, respectively. The particle size is controlled in these regions by adjusting the 18C6 molar ratio. XRD showed that zeolite rho samples with 18C6 molar ratios of 0.25-1.5 had high crystallinity. The adsorbed amount of CO2 is almost constant, at 3.4 mmol-CO2 g(-1), regardless of the 18C6 molar ratio. However, CO2 selectivity, which is the CO2/N-2 adsorption ratio, decreased. The amount of CO2 adsorbed on zeolite rho is lower than that on zeolite NaX, but higher than that on SAPO-34. The CO2/N-2 adsorption ratio for zeolite rho was higher than those for SAPO-34 and zeolite NaX. (c) 2012 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jcis.2012.06.061

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Monodisperse carbon spheres with coefficient of variation less than 4% were successfully synthesized through polycondensation of resorcinol with formaldehyde in the presence of ammonia as a catalyst followed by carbonization in an inert atmosphere. The diameters of the carbon spheres can be tuned in the range of 220-1140 nm by adjusting the ammonia concentration in the precursor solutions. Although the particle size decreases with increasing ammonia concentrations, there is no large difference in the internal pore structure between the different-sized carbon spheres. The size-controlled monodisperse carbon spheres were used as a model material to understand the ion storage/transfer behavior in electrical double-layer capacitor (EDLC). The present study clearly indicates that the reducing the particle size and highly monodispersity in both size and shape were effective at reducing mass transport resistance and improving EDLC performance reliability.

DOI： 10.1021/jp308415s

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

There are many viewpoints on the formation mechanisms for zeolites, but the details are not clear. An understanding of the elementary steps for their formation is important for the development of large-scale membranes and efficient manufacturing processes. In this study, the effects of silicon, aluminum, and the incorporation of 18-crown-6 (18C6) ether, on the formation of zeolite rho, using 18C6 as the structure directing agent (SDA) have been investigated by using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray fluorescence spectrometry (EDX), nuclear magnetic resonance spectroscopy (NMR), thermo gravimetric analysis (TGA), and the pH measurement. These results suggested that a zeolite rho has four synthesis steps; (1) 0-3 h, the dehydration and condensation reaction between the silica and alumina to form amorphous aluminosilicates; (2) 3-20 h, the particle growth and aggregation process for the amorphous aluminosilicates; (3) 20-48 h, the crystallization and crystal growth of zeolite rho, with the incorporation of 18C6; and (4)48-96 h, gentle growth with an increase in Na/Si ratio and a change in rate for the bounding state between the silica- and the alumina-based species. We consider the above to reflect the four steps for the formation of zeolite rho. (C) 2012 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jcis.2012.02.038

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

We report here a simple and straightforward method that enables the size-controlled production of zeolitic imidazolate framework-8 in an aqueous system at room temperature. Pure single crystals with the size tuned in the range of ca. 300 nm to 3 gm in mean crystal size can be obtained and exhibit ultrahigh Langmuir surface area of above 1800 m(2) g(-1).

DOI： 10.1246/cl.2012.1337

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

We report that photoactivated rutile titanium dioxide (TiO2) catalyzes a highly efficient and selective hydrogenation of nitroaromatics with alcohol as a hydrogen source. Photoirradiation (lambda &gt; 300 nm) of rutile TiO2 suspended in alcohol containing nitroaromatics at room temperature and atmospheric pressure produces the corresponding anilines with almost quantitative yields, whereas common anatase and P25 TiO2 show poor activity and selectivity. The Ti3+ atoms located at the oxygen vacancies on the rutile surface behave as the adsorption site for nitroaromatics and the trapping site for photoformed conduction band electrons. These effects facilitate rapid and selective nitro-to-amine hydrogenation of the adsorbed nitroaromatics by the surface-trapped electrons, enabling aniline formation with significantly high quantum yields (&gt;25% at &lt;370 nm). The rutile TiO2 system also facilitates chemoselective hydrogenation of nitroaromatics with reducible substituents; several kinds of functionalized anilines are successfully produced with &gt;94% yields.

DOI： 10.1021/cs300500p

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Visible light irradiation (lambda &gt;450 nm) of platinum (Pt) nanoparticles supported on anatase titanium dioxide (TiO2) promotes efficient aerobic oxidation at room temperature. This occurs via the electronic excitation of Pt particles by visible light followed by the transfer of their electrons to anatase conduction band. The positively charged Pt particles oxidize substrates, whereas the conduction band electrons are consumed by the reduction of molecular oxygen. The activity of this photocatalysis depends on the height of Schottky barrier and the number of perimeter Pt atoms created at the Pt/anatase heterojunction, which are affected by the amount of Pt loaded and the size of Pt particles. The catalyst loaded with 2 wt % Pt, containing 3-4 nm Pt particles, creates a relatively low Schottky barrier and a relatively large number of perimeter Pt atoms and, hence, facilitates smooth Pt -&gt; anatase electron transfer, resulting in very high photocatalytic activity. This catalyst is successfully activated by sunlight and enables efficient and selective aerobic oxidation of alcohols at ambient temperature.

DOI： 10.1021/cs300407e

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

TiO2 loaded with Au-Ag bimetallic alloy particles efficiently produces H2O2 from an O-2-saturated ethanol/water mixture under UV irradiation. This is achieved via the double effects created by the alloy particles. One is the efficient photocatalytic reduction of O-2 on the Au atoms promoting enhanced H2O2 Formation, due to the efficient separation of photoformed electron-hole pairs at the alloy/TiO2 heterojunction. Second is the suppressed photocatalytic decomposition of formed H2O2 due to the decreased adsorption of H2O2 onto the Au atoms.

DOI： 10.1021/cs2006873

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Visible-light irradiation (lambda &gt; 450 nm) of gold nanoparticles loaded on a mixture of anatase/rutile TiO2 particles (Degussa, P25) promotes efficient aerobic oxidation at room temperature. The photocatalytic activity critically depends on the catalyst architecture: Au particles with &lt;5 nm diameter located at the interface of anatase/rutile TiO2 particles behave as the active sites for reaction. This photocatalysis is promoted via plasmon activation of the Au particles by visible light followed by consecutive electron transfer in the Au/rutile/anatase contact site. The activated Au particles transfer their conduction electrons to rutile and then to adjacent anatase TiO2. This catalyzes the oxidation of substrates by the positively charged Au particles along with reduction of O-2 by the conduction band electrons on the surface of anatase TiO2. This plasmonic photocatalysis is successfully promoted by sunlight exposure and enables efficient and selective aerobic oxidation of alcohols at ambient temperature.

DOI： 10.1021/ja2120647

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

The carbon dioxide adsorption properties of zeolite Rho materials, containing various exchangeable cations have been investigated. All carbon dioxide adsorption properties were measured at a temperature of 25 degrees C over a pressure range of 0-100 kPa. The results show that the carbon adsorption properties are dependent on the cations present. The highest amount of CO2 absorbed, measured at 4.0 mmol g(-1), was obtained for a proton-exchanged zeolite Rho (H Rho), which was prepared by the calcination of NH4+-exchanged zeolite Rho at 350 degrees C.

DOI： 10.1246/cl.2012.125

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Language：Japanese   Publisher：THE CARBON SOCIETY OF JAPAN  

Ordered mesoporous carbons were synthesized by using an organic-organic self-assembly (soft-templating) method using resorcinol (R) / formaldehyde (F) and triblock copolymer Pluronic F127. A hexagonal mesostructure with channel like pores (COU-1) with a pore size of 4.7–5.8 nm and a 3D wormhole-like mesopore structure (COU-2) with a pore size of 4.8 nm were synthesized using precursor solutions with different mass ratios of F127/RF resin. The mesoporous carbons were activated by using KOH to improve their porosity. The KOH-activated COU-2 carbon showed superior capacitance compared to the COU-2 carbon and a commercial microporous carbon. Ultrathin carbon films with a monolayer of uniform mesopores were also synthesized on a silicon substrate by contacting a triblock copolymer film with a benzyl alcohol vapor followed by carbonization.

DOI： 10.7209/tanso.2011.70

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Other Link： http://hdl.handle.net/10112/5670

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

It is well known that the hydrothermal stability of silica is improved by adding zirconia, and porous silica-zirconia membranes (with 50 mol% zirconia) were prepared by sol-gel techniques. A homogeneous silica-zirconia composite sol, prepared by the hydrolysis and condensation reactions of tetraethoxysilane (TEOS) and zirconium n-butoxide (ZrB) in an ethanol solvent, gave uniform and defect-free membranes. Since it was necessary for the hydrolysis and condensation reaction rates of ZrB to be reduced because these reactions are faster than those of TEOS, the chemical reactivity of ZrB was modified with the chelating agent acetylacetone (acac). Silica-zirconia membranes were used for dehydration of isopropyl alcohol/water mixtures at 348 K by pervaporation to evaluate the effect of preparation conditions such as temperature, H(+)/(Si + Zr), H(2)O/(Si + Zr) and acac/Zr molar ratios on membrane performance. The silica-zirconia membranes had the highest separation factor of 62.5 when they were prepared with H(+)/(Si + Zr), H(2)O/(Si + Zr) and acac/Zr molar ratios 0.05, 4 and 0.6, respectively, and three coating cycles. The membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.desal.2010.07.067

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Semiconductor TiO2 particles loaded with WO3 (WO3/TiO2), synthesized by impregnation of tungstic acid followed by calcination, were used for photocatalytic oxidation of alcohols in water with molecular oxygen under irradiation at lambda &gt; 350 nm. The WO3/TiO2 catalysts promote selective oxidation of alcohols to aldehydes and show higher catalytic activity than pure TiO2. In particular, a catalyst loading 7.6 wt% WO3 led to higher aldehyde selectivity than previously reported photocatalytic systems. The high aldehyde selectivity arises because subsequent photocatalytic decomposition of the formed aldehyde is suppressed on the catalyst. The TiO2 surface of the catalyst, which is active for oxidation, is partially coated by the WO3 layer, which leads to a decrease in the amount of formed aldehyde adsorbed on the TiO2 surface. This suppresses subsequent decomposition of the aldehyde on the TiO2 surface and results in high aldehyde selectivity. The WO3/TiO2 catalyst can selectively oxidize various aromatic alcohols and is reusable without loss of catalytic activity or selectivity.

DOI： 10.1002/chem.201100166

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Hydrophobic silica membrane was prepared on a porous alumina support with gamma-alumina interlayer by a sol-gel method using tetraethoxysilane (TEOS) and phenyltriethoxysilane (PhTES). Cetyltrimethylammonium bromide (CTAB) was used to control the pore size by acting as a molecular template, and to improve the flux through the membrane. The effects of CTAB concentration and PhTES content in silica source on the membrane performance for pervaporation of EA/water were investigated. The phenyl-functionalized silica membranes were characterized by Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, contact angle measurement and single gas permeation measurement. The membranes were used for recovery of organic compounds by pervaporation separation of ethyl acetate (EA), methylethyl ketone (MEK) and isopropanol (IPA) in aqueous solutions. The permeation flux and separation factor of EA (5 wt%)/water at 313 K using the hydrophobic silica membrane were 1.94 kg m(-2) h(-1) and 216, respectively. The separation factor for pervaporation of EA/water was larger than that for vapor liquid equilibrium. The fluxes and separation factor of organic components had values in the order EA &gt; MEK &gt; IPA. We suggest that this result is based on the order of hydrophobicity of the organic compounds and kinetic diameter. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.memsci.2011.06.026

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

An alkylimidazolium-based long-chain ionic liquid (LCIL) was immobilized in silica nanopores via a supramolecular assembly approach. To discuss the characteristic features of LCIL in a confined nanospace, except for the characteristics of the host materials, we have prepared the silica host with monodisperse morphology and a nanostructured system to immobilize LCIL. The nanostructure is composed of three distinct regions: the silica framework, the hydrophobic interior of the alkyl chains, and the organic inorganic ionic interface. Anomalous CO2 adsorption sites were found to be well-ordered locations on the ionic interface fabricated by the a pi-pi-stacked imidazolium heads containing inorganic anions and polar silica surfaces.

DOI： 10.1021/la201431z

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Microporous carbon membranes for pervaporation applications were prepared on a porous a-alumina support by a partially carbonization of a resorcinol/formaldehyde resin. The stability and dehydration performances of the carbon membranes were determined. The carbon membranes were used for the dehydration of several organic solvents (methanol, ethanol, i-propanol, and acetic acid) containing water; it was found that water was selectively permeated through the membrane and the separation factor increased with the molecular diameter of the organic solvents. The high selectivity to water can be explained by not only the hydrophilic nature of the pore surface but also the molecular sieving effect. Furthermore, the membranes showed high durability in the pervaporation of water/alcohol mixtures. On the other hand, the membranes were unstable in water/acetic acid mixture. However, the sulfonated carbon membranes were stable in pervaporation of water/acetic acid mixture and maintained their separation properties. (C) 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.memsci.2011.05.046

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Improving the hydrogen permeation flux, while maintaining high hydrogen selectivity, is important for reducing membrane areas and enhancing membrane reactor (MR) performance. We have attempted to enhance the hydrogen permeation through the addition of nickel, which will improve both hydrogen adsorption and pore size control. The silica layer was deposited with high selectivity, using an extended counter-diffusion CVD method.

DOI： 10.1246/cl.2011.1159

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

UV irradiation of TiO2 loaded with bimetallic Pd-Pt alloy particles promotes highly efficient dehalogenation of organic halides with alcohol as a hydrogen source.

DOI： 10.1039/c1cc12087e

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DOI： 10.1039/c0cc05615d

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Preparation of continuous mesoporous carbon membranes without the use of an intermediate inorganic template was achieved using a thermosetting phenolic resin, resorcinol/phloroglucinol/formaldehyde, and a thermally-decomposable organic template, Pluronic F127 (PEO(106)-PPO(70)-PEO(106)). The coating solution was cast on porous alpha-alumina supports by dip-coating. Afterwards, decomposition of the organic template and solidification of the carbon precursors are simultaneously performed through a carbonization process. A composite layer of carbon/alumina was formed. The single gas permeation was governed by the Knudsen diffusion mechanism. The membrane exhibited high hydrothermal stability and high alkaline resistance. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carbon.2011.03.042

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

SAPO-34 nanocrystals were synthesized by a dry gel conversion method using tetraethylammonium hydroxide as a structure-directing agent. The crystal growth of SAPO-34 was studied by X-ray diffraction and field-emission scanning electron microscopy. After 3 h, 45-nm SAPO-34 crystals with an amorphous phase were observed. The crystal size increased to 70 nm after 6 h, but did not increase greatly thereafter. The average crystal size of the final product was 75 nm. The nucleation density for SAPO-34 crystals in dry gel conversion appeared to be much higher than that under hydrothermal conditions, resulting in the formation of small crystals. (C) 2010 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.matchemphys.2010.05.005

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DOI： 10.1007/s11244-009-9415-x

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Ordered mesoporous carbon (COU-2) was synthesized by a soft-templating method. The COU-2 mesoporous carbon was activated by using KOH to improve its porosity. The mesopore size of COU-2 was 5.5 nm and did not change by the KOH activation. But, the BET surface area of COU-2 largely increased from 694 to 1685 m(2)/g and total pore volume was increased from 0.54 to 0.94 cm(3)/g after the KOH activation. The large increase of micropore volume is due to the increase of the surface area. Electrochemical cyclic voltammetry measurements were conducted in aqueous (1 M sulfuric acid) and organic (1 M tetraethyl ammonium tetrafluoroborate/polypropylene carbonate) electrolyte solutions. The KOH-activated COU-2 carbon shows superior capacitances over the COU-2 carbon and a commercial microporous carbon both in aqueous and organic electrolyte solutions. These results suggest that the carbons having regularly-interconnected uniform mesopores and micropores in thin pore walls are desirable for the electrodes in electrochemical double-layer capacitors. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carbon.2010.02.005

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Hydrophobic organic-inorganic composite membranes with cross-linked poly(dimethyl siloxane)-poly(methyl hydrogen siloxane) (PDMS/PMHS) were prepared on a porous alumina tubular support. The PDMS/PMHS polymer penetrated into and plugged the pores of the gamma-alumina support. The membrane had an approximately 3.5-mu m-thick polymer/alumina composite layer. The alumina matrix inhibited the swelling of the PDMS/PMHS membrane. The pervaporation separation of an ethylacetate/water mixture with low percentages of ethylacetate was carried out with these composite membranes. The effect of the thermal treatment of the PDMS/PMHS membrane on the existence of silanol and methyl groups, and the flux and separation factor were investigated. The flux and separation factor were varied depending on the temperature of thermal treatment of the PDMS/PMHS membranes. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.memsci.2009.11.033

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DOI： 10.1002/anie.200906573

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Mesoporous silica microspheres (MSM) approximately 1.0 mu m in diameter were prepared by the hydrolysis and condensation of tetraethoxysilane (TEOS) under the presence of dodecylamine (DDA) as a molecular template and catalyst in ethanol-water solution. Isolated MSM were obtained in a narrow range of experimental conditions, which were experimentally correlated by the linear relationship between the molar ratio of ethanol and TEOS and that of DDA and TEOS. Isolated MSM modified with thiol groups were also prepared under similar experimental conditions, by co-condensation of TEOS and 3-mercaptopropyltrimethoxysilane (MPTMS). The thiol-functionalized MSM (SH-MSM) adsorbed silver ions from an aqueous solution. Asymmetrical polystyrene film, in which the SH-MSM were self-assembled on the surface of the water phase side of the film, was obtained by spreading and polymerizing of styrene monomer with dispersed SH-MSM on the water surface. The polymer film containing SH-MSM also effectively adsorbed silver ions.

DOI： 10.1021/ie800614c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Aminopropyl-functionalized mesoporous silica microspheres (AF-MSM) were synthesized by a simple one-step modified Stober method. Dodecylamine (DDA) was used as the catalyst for the hydrolysis and condensation of the silica Source and as the molecular template to prepare the ordered mesopores. The mesoporous silica surfaces were modified to aminopropyl groups by the co-condensation of tetraethoxysilane (TEOS) with 3-aminopropyltriethoxysilane (APTES), up to a maximum of 20 mol.% APTES content in the silica source. The particle size, Brunauer-Emmet-Teller (BET) specific surface area, and mesoporous regularity decreased with increasing APTES content. It is believed that this result is caused by a decreasing amount of DDA incorporated into AF-MSM with increasing APTES content. It was also confirmed that the spherical shape and the mesostructure were maintained even if 20 mol.% of APTES was added to the silica source. Moreover, AF-MSM was applied to the CO2 adsorbent. The breakthrough time of the CO2 and CO2 adsorption capacities increased with increasing APTES content. The adsorption capacity of CO2 for AF-MSM, prepared at 20 mol.% APTES, was 0.54 mmol g(-1). Carbon dioxide adsorbed onto AF-MSM was completely desorbed by heating in a N-2 purge at 423 K for 30 min. (C) 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jcis.2009.07.024

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DOI： 10.1016/j.jphotochem.2009.04.001

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Morphology control of ordered mesoporous carbon was performed using an organic-organic interaction approach. Mesoporous carbons were synthesized from a resorcinol-phloroglucino/formaldehyde polymer and triblock copolymer Pluronic F127 in ethanol-water solutions of different molar ratios. A face-centered orthorhombic Fmmm structure was formed in the film prepared by dip-coating method. A three-dimensional wormhole-like mesostructure was formed during powder preparation at EtOH/water molar ratios ranging from 0.5 to 1.25. When the molar ratio was further increased to 2.5, a hexagonal p6mm structure was obtained. The pore size of the mesoporous carbon powders increases with increasing EtOH/water molar ratio. A dual-templating approach was demonstrated to prepare mesoporous carbon nanofibers. Anodic aluminum oxide membranes were used as a hard template. A mesostructure with a short-range order was formed and oriented along the surface in different directions. The structural order became distorted in the interior region. (C) 2009 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carbon.2009.05.024

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Mesoporous silica microspheres (MSM) approximately 1.0 mu m in diameter were prepared by the hydrolysis and condensation of tetraethoxysilane (TEOS) under the presence of dodecylamine (DDA) as a molecular template and catalyst in ethanol-water solution. Isolated MSM were obtained in a narrow range of experimental conditions, which were experimentally correlated by the linear relationship between the molar ratio of ethanol and TEOS and that of DDA and TEOS. Isolated MSM modified with thiol groups were also prepared under similar experimental conditions, by co-condensation of TEOS and 3-mercaptopropyltrimethoxysilane (MPTMS). The thiol-functionalized MSM (SH-MSM) adsorbed silver ions from an aqueous solution. Asymmetrical polystyrene film, in which the SH-MSM were self-assembled on the surface of the water phase side of the film, was obtained by spreading and polymerizing of styrene monomer with dispersed SH-MSM on the water surface. The polymer film containing SH-MSM also effectively adsorbed silver ions.

DOI： 10.1021/ie800614c

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Monodisperse titania spheres with particle diameters in the range 380-960 nm were successfully synthesized by hydrolysis and condensation of titanium tetraisopropoxide. The preparation was performed using ammonia or dodecylamine (DDA) as a catalyst in methanol/acetonitrile co-solvent at room temperature. The samples were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and nitrogen sorption measurement. The use of DDA was effective for the synthesis of monodisperse titania spheres with low coefficient of variation. When the titania spherical particles with coefficient of variation less than 4% were obtained, the colloidal crystallization easily occurred simply by centrifugation. The monodispersity was maintained even after crystallization of the particles by high temperature annealing. The titania particles prepared using DDA had mesopores near the Surface of the spheres, providing high pore accessibility to the sphere from the surface-air interface. The particle size uniformity and photocatalytic reactivity of the titania prepared using DDA were higher than those of the titania prepared using ammonia. (C) 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jcis.2009.02.060

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Highly ordered cubic mesoporous aluminosilicates were synthesized using PEO106PPO70PEO106 triblock copolymer and aluminosilicate sols containing Si-O-Al bonds, which are obtained by dissolving Na-A type zeolite in HCl, under mild acidic conditions (pH 1.9-3.2).

DOI： 10.1246/cl.2009.780

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Magnetite-containing spherical mesoporous silica (M-SMS) has been prepared using the phase transfer method between an aqueous phase containing cationic surfactant and magnetite nanoparticles and an oil phase consisting of hydrophobic tetrabutoxysilane (TBOS) as the silica source under stirring conditions. The M-SMS was 200-300 mu m in diameter and possessed mesopores with a mean diameter of ca. 2 nm and a high BET surface area of over 960 m(2)/g. M-SMS could be easily collected and separated from the solution using a magnet. The following mechanism is proposed for the formation of the M-SMS: the magnetite nanoparticles are transferred with a cationic surfactant (cetylpyridinium chloride, CPC) and water molecules from the aqueous phase into the oil phase of TBOS. The W/O-type microemulsions are formed in the TBOS phase, and the hydrolysis and condensation of TBOS proceed subsequently at the interface and/or in the water pools of the microemulsions; thus, magnetite nanoparticles are loaded in a silica matrix. In this system, CPC acted as a structure-directing agent for formation of mesopores and as a phase transfer agent for magnetite nanoparticles. Butanol molecules, released by hydrolysis of TBOS, are thought to behave as a cosolvent for the phase transfer of magnetite nanoparticles.

DOI： 10.1021/ie8012133

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Zeolite Na-A crystals dissolved in a HCl solution were used as a single-source of silicon and aluminum for the synthesis of mesoporous aluminosilicates via a template-assisted method with an organic base tetramethylammonium hydroxide (TMAOH). Amphiphilic triblock copolymer Pluronic F127 (EO(106)PO(70)EO(106)) was used as template. Increasing the amount of TMAOH in the synthetic solution resulted in an increase in the aluminum content of the products. On the other hand, mesostructural periodicity was deteriorated with higher content of aluminum incorporated into the mesoporous framework. The samples with low Si/Al ratios less than 5 have wormhole-like pore structure, while the samples with Si/Al ratios more than 7 possess highly ordered mesoporous structure, a body-centered lm3m symmetry, with single crystal like morphology. The samples with Si/Al ratio of 7, which prepared at TMAOH molar concentration of 25 mM in the templating solution, possess BET Surface area of 470 m(2)/g, pore size of 6.4 nm, and pore volume of 0.56 cm(3)/g. Aluminum atoms have successfully been incorporated in a tetra-coordinated position and remained stable even after calcination at 600 degrees C. (C) 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jcis.2009.01.054

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Zeolite Na-A dissolved in a HCl solution was used as aluminum and silica precursors for the synthesis of mesoporous aluminosilicates via a template-assisted method with an organic base tetramethylammonium hydroxide (TMAOH). Increasing the amount of TMAOH in the synthetic solution resulted in an increase in the aluminum content of the products. On the other hand, mesostructural periodicity was deteriorated with higher content of aluminum substituted in the framework. The samples with low Si/Al ratios less than 5 have wormhole-like pore structure, while the samples with Si/Al ratios more than 7 have highly ordered mesoporous structure with crystal like morphology.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Preparation of ordered mesoporous carbon films without the use of an intermediate inorganic silica template was achieved from organic-organic assembly of thermally-decomposable triblock copolymer and thermosetting phenolic resin precursors. The films were formed by spin-coating followed by an evaporation-induced self-assembly. Afterwards, decompositon of the organic template and solidification of the carbon precursors are simultaneously performed through a direct carbonization process. Adjusted condition in the ratio of phenolic resin precursors and triblock copolymer allows one to tailor the final mesostructure which include 2D hexagonal phase (c2mm) and 3D face-centered orthorhombic symmetry (Fmmm). These film periodicity uniaxially-contracted normal to the film surface.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Spin-on mesostructured films were prepared from tetraethoxysilane (TEOS) as a silica source and nonionic triblock copolymer Pluronic F 127 as a templating agent. The films were treated with trimethylethoxysilane (TMES) vapor before and/or after calcination. The porosity of the calcined films was increased with a rise of the molar ratio of F127/TEOS in the precursor solutions. The TMES vapor treatments reduced refractive index of the mesoporous silica films to 1.23 and effectively improved their mechanical strength. (C) 2008 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.colsurfa.2007.12.012

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

Mesoporous silica films have been prepared by a vapor phase method using tetraethoxysilane (TEOS) in a batch reactor and in a continuous flow reactor. The TEOS molecules penetrated into a triblock copolymer films and then a triblock copolymer/silica composite structure was formed. A two dimensional grazing-incidence small angle X-ray scattering pattern and field emission scanning electron microscopy images of the films indicated that the films possess ordered and disordered regions. The tortuous pore channels in the wormhole-like disordered structure run parallel to the film surface. The mesostructured triblock copolymer/silica composite films were treated with a trimethylethoxysilane (TMES) vapor before and after calcination. The vapor infiltration treatments effectively improved mechanical strength and hydrothermal stability of the films. The dielectric constant of the TMES-treated mesoporous silica films was reduced into the 1.5-1.7 range. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2007.08.124

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Silicalitc-1 zeolite crystals with mesoporosity were prepared by hydrothermal synthesis mediated by structure-directing agents (SDA) using mesoporous carbon-silica nanocomposites as starting materials. These materials have ordered structures with channel mesopores and mesochannel walls made up of carbon and silica. The growth of zeolite crystals took place inside the open mesospace without the collapse of the ordered mesostructure during hydrothermal synthesis at optimized molar ratios of tetrapropylammonium hydroxide and bromide. The disordered mesoporosity, which slightly persisted as a vestige of channel structure, was introduced into the zeolite crystals even after the removal of the carbon part of the framework, though a small amount of amorphous silica was remained. (C) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.micromeso.2007.12.001

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ELSEVIER SCIENCE BV  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Preparation of well-ordered continuous mesoporous carbon films without the use of an intermediate inorganic template was achieved by spin coating of a thermosetting phenolic resin, resorcinol/ phloroglucinol/formaldehyde, and a thermally-decomposable organic template, Pluronic F127 ( PEO106-PPO70-PEO106). The carbon films were deposited onto silicon, platinum/silicon, copper, glass, and quartz substrates. Afterwards, decomposition of the organic template and solidification of the carbon precursors are simultaneously performed through a carbonization process. The resulting films referred to as CKU-F69, are (010)-oriented, and possess a facecentered orthorhombic Fmmm symmetry. Film periodicity is maintained even after a 68% uniaxial contraction perpendicular to the substrate brought on by carbonization at 800 degrees C. This method could facilitate the mass- production and creation of new carbon and carbon - polymer porous films that find broad potential applications in catalysis, separation, hydrogen storage, bioengineering, nanodevices, and nanotemplates.

DOI： 10.1039/b705692c

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：ELSEVIER SCIENCE BV  

The adsorption and phase behavior of krypton at 87.3 K (i.e. 28.5 K below krypton's triple point temperature) has been systematically studied as a function of pore size by using a series of micro-and mesoporous molecular sieves. Our results indicate that pore condensation of krypton cannot be observed for pore diameters &gt; 10 nm, but occurs in smaller mesopores. An important result is further that the density of the confined krypton phase at 87.3 K corresponds to the density of supercooled liquid krypton, which is important for applying krypton adsorption for pore size analysis. We used the results of our systematic krypton adsorption studies to develop a method for the characterization of thin micro/mesoporous silica films based on krypton adsorption at liquid argon temperature (87.3 K). This method allows determining the pore size distribution of thin films in the pore diameter range from &lt; 1 to similar to 9 nm.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

Ordered mesoporous silica films have been prepared by spin-coating using tetraethoxysilane (TEOS) as a silica source and nonionic surfactant Brij 30 as a templating agent. Sulfuric acid (H2SO4), nitric acid (HNO3), or hydrochloric acid (HCl) was mixed as a catalyst in coating solutions. A vapor infiltration treatment was performed using TEOS or trimethylethoxysilane (TMES). The vapor infiltration treatments effectively improved mechanical strength, hydrothermal stability and film adhesive. The dielectric constant of the TMES-treated mesoporous silica film was 1.8. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2005.08.218

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Ordered mesoporous zirconium phosphate films were prepared on a silicon substrate by spin coating using a mixture of zirconium isopropoxide, triethyl phosphate, Pluronic P123 triblock copolymer, nitric acid, ethanol, and water. The spin-on film was consecutively treated with vapors of phosphoric acid and ammonia. The post-vapor treatments effectively enhanced the thermal stability of an ordered mesostructure when heated to 500 degrees C. XRD and TEM analyses show that the calcined zirconium phosphate film has a hexagonal structure with straight channels parallel to the film surface. The zirconium phosphate film exhibited high proton conductivity of 0.02 S/cm parallel to the film surface at 80% RH and 25 degrees C.

DOI： 10.1021/la061493+

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Highly ordered mesoporous silica thin films with c2mm rectangular and R3m rhombohedral symmetry have been synthesized on a silicon substrate by a vapor-phase method using PEO106-PPO70-PEO106 triblock copolymer as a templating agent.

DOI： 10.1246/cl.2006.928

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Highly ordered mesoporous silica thin films have been prepared on silicon substrates by contacting PEO106-PPO70-PEO106 (Pluronic F127) triblock copolymer films with hydrolyzed tetraethyl orthosilicate (TEOS) followed by calcination. 2D grazing angle of incidence small angle X-ray scattering (GISAXS) patterns analyzed in the context of the distorted wave Born-approximation (DWBA) show that the films are (111)-oriented and possess rhombohedral symmetry with lattice constants a = 16.8 nm and alpha = 70 degrees. Further, high resolution field emission scanning electron microscope (FESEM) observations showed that the films have a lamellar structure supported with periodically arranged pillars. To our knowledge this is the first report of a rhombohedral mesophase obtained using Pluronic F127. Additionally, the pore connectivity in the films here differs from previously reported rhombohedral films. Here the films are capped with a dense layer of silica and appear to not have significant mesoporosity in the direction perpendicular to the substrate. As a result of this structure, after silylation the films have a low relative dielectric constant of similar to 1.86. In addition, by comparing the X-ray diffraction (XRD) patterns with the GISAXS analysis, we show how using Bragg's law to calculate d-spacings from XRD data can significantly underestimate the d-spacing. Taking into account the effects of refraction, we report a modified expression of Bragg's law that may be used to recover accurate d-spacings from XRD data.

DOI： 10.1021/cm0614463

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Mesoporous carbons with ordered channel structure (COU-1) have been successfully fabricated via a direct carbonization of an organic-organic nanocomposite.

DOI： 10.1039/b501259g

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Hexagonally arranged surfactant-catalyst composites were treated only with tetraethoxysilane vapor, resulting in the formation of the silica mesostructures without phase transition.

DOI： 10.1246/cl.2005.1148

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Organically functionalized mesoporous silica films have been prepared by a novel synthetic procedure that involves spin-coating of mesostructured silica films and a vapor infiltration (VI) technique, using organosiloxanes, before the removal of surfactant. The VI-treated mesostructured films were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and a field emission scanning electron microscope (FE-SEM). Nitrogen adsorption/desorption measurements were performed using films attached with a silicon substrate. The XRD and FE-SEM measurements show that the mesochannel wall, densified and modified with organosilyl groups by the VI treatment, hardly contracts under calcination. FE-SEM observations for the films' cross section support the view that organosiloxane vapor is not deposited on the surface of the film. These results show that organosiloxane molecules penetrate the film and are selectively incorporated into the silica wall. Thus, hydrophobic mesoporous silica films can be synthesized without a reduction in pore size, a result that cannot be attained by conventional grafting and co-condensation methods. The excellent high porosity and hydrophobicity of the mesostructured composite films may be of advantage for next-generation low-k dielectric films.

DOI： 10.1021/la036453+

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：The Society of Chemical Engineers, Japan  

Mesoporous silica films with two-dimensional cage structure were prepared on a silicon substrate by a vapor phase synthesis. Vapor of tetraethoxysilane (TEOS) was infiltrated into a surfactant film consisting of triblock copolymer. The mesostructure of the thin films was characterized by X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) observations. Nitrogen adsorption/desorption measurements were performed using films on the silicon substrate and powdery sample which was peeled from the silicon substrate. The mesostructured silica thin films have silicate layers with ordered pillars and are isotropic parallel to the film surface. The structure of pores of the films is of advantage for next-generation low-k films. The mesoporous structure has a large lattice parameter <I>d</I> of ~102Å, silica layer thickness of ~58Å, pillar diameter in the middle of ~60Å, pore size of ~72Å, BET surface area of ~729 m<SUP>2</SUP>/g, and pore volume of ~1.19 cm<SUP>3</SUP>/g. The films show high thermal stability up to 900°C and high hydrothermal stability. This method is a simpler process than conventional sol-gel techniques and attractive for mass production of a variety of organic-inorganic composite materials and inorganic porous films.

DOI： 10.11491/apcche.2004.0.71.0

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：The Society of Chemical Engineers, Japan  

Spin-coating method is a simple way to synthesize nanostructured silica films. However, the thin films by spin-coating have low thermal stability because the reactions proceed at room temperature. In this study, we have developed a vapor treatment using a silica source for spin-on nanostructured silica films to improve the structural stability. The vapor treatment promotes condensations of silanol groups. The silica wall is densified and hardly contracts under a calcinations process. This indicates that vapor treatments effectively enhance structural stability. We have studied effect of vapor treatments on mechanical strength and hydrothermal stability of the nanoporous silica films prepared from tetraethoxysilane (TEOS)/Brij 30 (C<SUB>12</SUB>(EO)<SUB>4</SUB>) mixtures. The results of pressure tests and hot water-resisting tests show that the vapor-treated films exceed non-treated films in mechanical strength and hydrothermal stability. The vapor-treated nanoporous silica films are promising materials as low-<I>k</I> films with high mechanical strength and high porosity.

DOI： 10.11491/apcche.2004.0.643.0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Novel mesostructured silica thin films were prepared on a Si substrate by a vapor-phase synthesis. Vapor of tetraethoxysilane (TEOS) was infiltrated into a surfactant film consisting of a poly(ethylene oxide)poly(propylene oxide) - poly(ethylene oxide) triblock copolymer. Nanophase transition from a lamellar structure to a two-dimensional cage structure of a silica-surfactant nanocomposite was found under vapor infiltration. The rearrangement into the cage structure implies high mobility of the silica-surfactant composites in solid phase. The silica thin films have two-dimensionally connected cagelike mesopores and are isotropic parallel to the film surface. The structure of pores of the films is advantageous for next-generation low-k films. The mesoporous structure has a large lattice parameter d of similar to102 Angstrom, silica layer thickness of similar to58 A, pillar diameter in the middle of similar to60 Angstrom, pore size of similar to72 Angstrom, BET surface area of similar to729 m(2)/g, and pore volume of similar to1.19 cm(3)/g. The films synthesized by the vapor infiltration show a lower concentration of residual Si-OH groups compared to the films prepared by a conventional sol-gel method. The films show high thermal stability up to 900degreesC and high hydrothermal stability. This method is a simpler process than conventional sol-gel techniques and attractive for mass production of a variety of organic-inorganic composite materials and inorganic porous films.

DOI： 10.1021/ja039267z

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：CHEMICAL SOC JAPAN  

Ultrathin silica films with a monolayer of uniform nanopores were fabricated on a silicon substrate by contacting triblock copolymer films with tetraethoxysilane vapor followed by calcination to remove the copolymer.

DOI： 10.1246/cl.2004.1408

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

A mesoporous silica has been prepared by base-catalyzed hydrolysis and polymerization of silicate ions followed by a vapor infiltration (VI) treatment using tetraethoxysilane (TEOS). X-ray diffraction analyses suggested that the VI-treated mesostructured silica did not contract during calcination, showing high structural stability. Fourier-transform infrared spectroscopy studies confirmed that a high density of surfactant molecules remained inside the pores during the VI treatment. The pore wall density increased after the VI treatment. The change in weight of mesostructured silica under VI treatment, and nitrogen adsorption/desorption studies, demonstrated that TEOS molecules penetrated into originally deposited silicate but did not deposit on the outer surface of particles and inside the pores. The denser pore wall of the VI-treated mesostructured silica has a high structural stability and hardly contracts under calcination. This post-synthesis method provides good support for the preparation of mesoporous silica with high structural stability and can also be applied to film preparation. (C) 2003 Elsevier Inc. All rights reserved.

DOI： 10.1016/S1387-1811(03)00453-0

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

Nano-phase transition of an organic-inorganic nanocomposite under vapor infiltration of tetraethoxysilane (TEOS) or tetramethoxysilane (TMOS) was found in mesoporous thin film preparation. The rearrangement into a hexagonal periodic structure implies high mobility of the surfactant-silicate composites in solid phase. The swelling of film thickness and d spacing was observed under vapor infiltration. The nano-phase transition under vapor infiltration contains two competitive processes: (1) the penetration of TEOS or TMOS into the film and (2) the reaction of the silanol group. Film thickness and d spacing were controlled by changing synthetic temperature, silica sources (TEOS and TMOS), catalysts (HCl and NH3), and the thickness of surfactant films. The films prepared from vapor phase show superior characteristics, such as high structural stability and high resistance to water adsorption. The vapor infiltration method is a simpler process than conventional sol-gel techniques and attractive for mass production of a variety of organic-inorganic composite materials and inorganic porous films.

DOI： 10.1021/cm021011p

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Publishing type：Research paper (scientific journal)  

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：MATERIALS RESEARCH SOCIETY  

Organically functionalized mesoporous silica films were prepared by a novel synthesis procedure. The synthesis procedure involves a vapor infiltration technique for mesostructured silica films prepared through a spin-coating process. Organic-functional groups were incorporated into the mesochannel wall by the vapor infiltration treatment using organosiloxanes. The structural stability of spin-on mesostructured silica films is generally low, resulting in a structural shrinkage or a collapse of the mesostructure under calcination process. On the other hand, the treated films did not contract during calcination, indicating high structural stability. A contact angle of water on the treated film was large, showing high hydrophobicity. FTIR analysis suggested that the residual silanol groups were replaced with the organosilyl groups after vapor infiltration treatment. The increase in the film thickness was hardly observed under vapor infiltration, suggesting no deposition of organosiloxanes vapor on the surface of the film.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：MATERIALS RESEARCH SOCIETY  

A novel synthesis route for mesostructured silica films is reported. Nano-phase transition from lamellar phase of surfactant to hexagonal phase of silica-surfactant nanocomposite was found under vapor infiltration. Vapor infiltration was performed using HCl as catalyst source and tetraethoxysilane (TEOS) as framework source. Highly ordered mesostructured silica films are obtained using alkyltrimethylammonium bromide CnTAB (the carbon number in the alkyl chain; n = 8, 10, 12, 14, 16, 18) as templating agent. The d values of the mesostructured silica films increase with increasing the length of the alkyl chain and are controllable by the synthetic temperature. The vapor infiltration synthesis is a simpler process compared to conventional sol-gel techniques and attractive for mass production of a variety of organic-inorganic composite materials and inorganic porous materials. This novel synthetic method provides opportunities for the creation of new materials technologies.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：MATERIALS RESEARCH SOCIETY  

We have recently developed novel periodic nanoporous silicate glass with high structural stability as low-k thin film by spin-coating method. Periodic porous silicate glass films developed so far cause structural shrinkage (10similar to20% or more) by annealing the spin-coated films. In this investigation we adopt vapor-phase TEOS (tetraethoxysilane)-treatment before anneal. Our novel nanoporous film shows little shift of XRD peak position after annealed at 673K, indicating both the ultimate mechanical strength and the minimization of stress in the interface between the prepared film and the underlying substrate. Such a shrinkage-free periodic nanoporous silica film can possess higher V-BD (break down voltage) and lower I-LEAK (leakage current). In this article we estimate structural properties (including information on pores introduced intentionally) by XRD and TEM observation, and electrical properties (dielectric constant, V-BD and I-LEAK) by IV and CV measurement of this special-treated periodic nanoporous silica film. The dielectric constant of the thus prepared periodic porous silica film with silylation after calcination was evaluated to be around 1.8 at 100kHz.

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Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：MATERIALS RESEARCH SOCIETY  

A mesoporous silica film was prepared on a silicon substrate using a spin-coating process followed by a tetraethyl orthosilicate (TEOS) vapor treatment. The stability of a formed silica network before TEOS treatment is thought to be insufficient because the rate of the condensation reaction is not high at temperatures below 453 K. The density of silica wall surrounding surfactant assembly could be low, resulting in the structural contraction with the formation of a silica network. On the other hand, the TEOS-treated mesoporous silica film did not contract during calcination, showing high structural stability. In the TEOS treatment, TEOS molecules penetrate into an originally deposited silicate film and react with silanol groups. The densified silica wall has high structural stability and hardly contracts under a calcination process. A flat mesoporous silica film about 250 nm thick was grown from the silicon substrate. A periodic hexagonal porous structure was observed in the FE-SEM image of the cross section of the TEOS-treated film. This indicates that the channels run predominantly parallel to the surface of the silicon substrate. The developed film is a promising material such as chemical sensors, low-k films and other optoelectronic devices.

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

A mesoporous silica film was prepared on a silicon substrate using a spin-coating process followed by a tetraethyl orthosilicate (TEOS) vapor treatment. The TEOS-treated mesostructured silica film did not contract during calcination, showing high structural stability. Thermal treatment without TEOS vapor was not effective to enhance the structural stability of mesostructured films. A flat mesoporous silica film about 250 nm thick was grown from the silicon substrate. No silica particle was deposited from TEOS vapor on the surface of the film, suggesting the penetration of TEOS vapor into the film. A periodic porous structure was observed in the FE-SEM image of the cross section of the mesostructured film. This indicates that the channels run predominantly parallel to the surface of the silicon substrate. FTIR studies suggested that the silanol groups in the film significantly decreased after the TEOS treatment. TEOS molecules penetrate into an originally deposited silicate film and react with the silanol groups. The densified silica wall has high structural stability and hardly contracts under a calcination process. The developed TEOS-treated mesoporous silica film is a promising material such as chemical sensors, low-k films, and other optoelectronic devices.

DOI： 10.1021/cm0201246

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Publisher：化学装置  

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Publisher：月刊ファインケミカル  

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Publisher：Zeolite  

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Publisher：The Membrane Society of Japan  

DOI： 10.5360/membrane.45.286

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Publisher：ケミカルエンジニヤリング  

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Publisher：The Membrane Society of Japan  

DOI： 10.5360/membrane.44.2

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Publisher：膜（Membrane）  

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Publisher：化学工学年鑑2018  

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Publisher：The Membrane Society of Japan  

DOI： 10.5360/membrane.43.224

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Publisher：日本膜学会会報  

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Publisher：Adsorption News  

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Publisher：The Membrane Society of Japan  

DOI： 10.5360/membrane.41.165

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Publisher：触媒  

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Publisher：ペトロテック  

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Publisher：関西大学理工学会会報  

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Publisher：化学工学年鑑2014  

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Publisher：A-STEP 技術移転シーズ紹介集（平成23年度終了課題分）  

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Publisher：化学工学年鑑2012  

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Publisher：科学と工業  

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Publisher：Chemical Engineering of Japan  

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Publisher：Adsorption News  

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Publisher：化学工学  

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Language：Japanese   Publisher：The Carbon Society of Japan  

Ordered mesoporous carbons were synthesized by using an organic-organic self-assembly (soft-templating) method using resorcinol (R) / formaldehyde (F) and triblock copolymer Pluronic F127. A hexagonal mesostructure with channel like pores (COU-1) with a pore size of 4.7–5.8 nm and a 3D wormhole-like mesopore structure (COU-2) with a pore size of 4.8 nm were synthesized using precursor solutions with different mass ratios of F127/RF resin. The mesoporous carbons were activated by using KOH to improve their porosity. The KOH-activated COU-2 carbon showed superior capacitance compared to the COU-2 carbon and a commercial microporous carbon. Ultrathin carbon films with a monolayer of uniform mesopores were also synthesized on a silicon substrate by contacting a triblock copolymer film with a benzyl alcohol vapor followed by carbonization.

DOI： 10.7209/tanso.2011.70

CiNii Books

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Other Link： http://hdl.handle.net/10112/5670

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Publisher：ケミカルエンジニヤリング  

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Publisher：ペトロテック  

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Publisher：炭素素原料科学と材料設計VIII, CPC研究会  

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Publisher：The Membrane Society of Japan  

DOI： 10.5360/membrane.28.177

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Event date： 2019.3

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Event date： 2019.1

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Event date： 2018.12

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Event date： 2018.11

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Event date： 2018.11

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Event date： 2018.11

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Event date： 2018.9

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Event date： 2018.9

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Event date： 2018.9

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Event date： 2018.9

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Event date： 2018.8

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Event date： 2018.8

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Event date： 2018.8

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Event date： 2018.8

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Event date： 2018.6

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Event date： 2018.5

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Event date： 2018.4

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Event date： 2018.3

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Event date： 2017.11

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Event date： 2017.11

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Event date： 2017.10

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Event date： 2017.10

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Event date： 2017.10

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Event date： 2017.9

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Event date： 2017.8

Venue：宮島コーラルホテル  

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Event date： 2017.5

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Event date： 2017.5

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Event date： 2016.8

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Event date： 2016.7

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Event date： 2016.7

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Event date： 2016.7

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Event date： 2016.3

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Event date： 2015.12

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Event date： 2015.10

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Event date： 2015.7

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Event date： 2015.7

Venue：Sapporo, Japan  

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Event date： 2014.11

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Event date： 2014.11

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Event date： 2014.11

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Event date： 2014.10

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Event date： 2014.10

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Event date： 2014.9

Venue：Leipzig, Germany  

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Event date： 2014.9

Venue：Leipzig, Germany  

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Event date： 2014.9

Venue：Leipzig, Germany  

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Event date： 2014.9

Venue：Leipzig, Germany  

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Event date： 2014.9

Venue：Leipzig, Germany  

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Event date： 2014.7

Venue：Louvain-la-Neuve, Belgium  

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Event date： 2013.12

Venue：Busan, Korea  

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Event date： 2013.12

Venue：Busan, Korea  

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Event date： 2013.11

Venue：JST東京本部別館ホール  

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Event date： 2013.11

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Event date： 2013.9

Venue：Australia, Brisbane  

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Event date： 2013.9

Venue：Australia, Brisbane  

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Event date： 2013.9

Venue：Australia, Brisbane  

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Event date： 2013.9

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Event date： 2013.6

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Event date： 2013.6

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Event date： 2013.5

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Event date： 2013.5

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Event date： 2013.5

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Event date： 2012.11

Venue：Kyoto, Japan  

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Event date： 2012.11

Venue：Kyoto, Japan  

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Event date： 2012.10

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Event date： 2012.9

Venue：Wellington, New Zealand  

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Event date： 2012.9

Venue：Wellington, New Zealand  

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Event date： 2012.9

Venue：Wellington, New Zealand  

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Event date： 2012.9

Venue：Wellington, New Zealand