担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Today  

Twinned structure of metal nanoparticles can strongly affect catalysis because of its unique atomic alignment and bond strain in metal nanoparticles. Here, the twin and single crystal structures of supported Ag nanoparticles are controlled reversibly by gas treatment. The single crystal Ag nanoparticles were formed in Ag/Al2O3 by H2 treatment, and subsequent CO gas treatment changed the Ag particle structure to twin. The change in the Ag particle structure from single to twin caused enhancement of CO oxidation activity. In addition, the catalytic activity was reversibly changed from low to high by applying H2 and CO gas treatment to Ag/Al2O3. The kinetic analysis for CO oxidation revealed that the twin Ag nanoparticles have stronger CO adsorption energy than the single crystal ones, which is responsible for the enhanced CO oxidation activity of twin Ag nanoparticles.

DOI： 10.1016/j.cattod.2022.06.029

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Surveys from Asia  

A combination of two base-metal oxides in tandem configuration can realize three-way reaction without platinum group metals. For this purpose, catalysts for hydrocarbon preferential oxidation (HC-PROX) and for NO reduction by CO are required. For the design of HC-PROX catalysts, competitive oxidation of propene and CO on spinel-type MFe2O4 (M = Co, Cu, Mg, Mn, Ni, Zn) was investigated. MnFe2O4 preferentially oxidized propene in the co-presence of CO showing the best propene oxidation activity. Among the series of MFe2O4, the activity controlling factor was correlated to the M-O bond energy of the second metal oxides, and the preference for HC oxidation was dependent on the electronegativity of the second ion. A tandem catalyst using MnFe2O4 for HC-PROX and CuCo2O4 for NO-CO reaction showed TWC activity comparable to a Rh/CeO2.

DOI： 10.1007/s10563-022-09373-9

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Surface Science  

We theoretically investigated surface modification of MCr2O4 (M = Mg and Zn) by Cu-doping and doping effects on catalytic activity for CO oxidation. DFT + U calculations elucidated that Cu-dopants in MCr2O4(1 1 1) exist on the surface layer, CO oxidation by Cu-doped MCr2O4(1 1 1) occurs through Mars van Krevelen mechanism, rate-determining step (RDS) is the first CO2 desorption with oxygen vacancy (OV) formation, and the catalytic activity is enhanced very much by Cu-doping. Also, we experimentally observed that CO conversion was dramatically improved to 70% by the Cu-doped ZnCr2O4 from 5.2% by non-doped ZnCr2O4 at 300 °C. Bader charge analysis and difference density map show that M atom on the MCr2O4 surface receives electron density from the dissociating O atom in the OV formation step and the Cu-dopant can receive more electron density than Mg and Zn atoms to facilitate the OV formation and accelerate the first CO2 desorption(RDS). This larger capability of Cu-dopant for receiving electron density results from the facts that the Cu atom has large electronegativity and + I oxidation state besides + II in metal oxide but Mg and Zn have small electronegativity and only + II oxidation state.

DOI： 10.1016/j.apsusc.2022.154681

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Science and Technology  

Direct catalytic conversion of methane to value-added chemicals with a high reaction rate and selectivity under mild conditions remains a great challenge. Rh-supported zeolite is one of the promising heterogeneous catalysts capable of selectively oxidizing methane to acetic acid using carbon monoxide and oxygen at low temperatures. However, the difficulty in the preparation of the catalytically active species, i.e., zeolite-confined RhI single-atom sites, has limited the mass activity. Here, we successfully prepared a highly-active Rh-containing zeolite using RhCl3 molten salt. By high-temperature treatment of the physically-mixed H+-MFI zeolite and bulk RhCl3, the RhCl3 molten salt was formed under in situ conditions and then diffused into the zeolite pores, resulting in being trapped within the zeolite cavity via host-guest interaction and ion-exchange with H+. The encapsulated RhCl3 species are efficiently dispersed with the formation of RhI single-atom species as the active sites in the catalytic reaction, boosting the direct conversion of methane to acetic acid with a record turnover frequency (592 mol molRh−1 h−1) and yield (14.6 mmol gcat−1 h−1) with high selectivity (76.9%).

DOI： 10.1039/d2cy01471h

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担当区分：最終著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Science and Technology  

A Pt-based CO oxidation catalyst that works even at low temperatures is desirable for industrial applications; however, its development is highly challenging because of Pt's high affinity toward CO. Here, we develop a PtIV single-atom/β-MnO2 composite metal-oxide surface (PtIV1/β-MnO2). Single PtIV sites were stably formed on the high surface β-MnO2 by strong interaction with MnIV defect sites. The resulting PtIV-O-MnIV local structures served the lattice oxygens as an oxidant to catalyze low-temperature oxidation of CO. PtIV1/β-MnO2 was highly resistant to CO poisoning because of the high-valence state of the PtIV single-atom sites. Aided by these geometric and electronic features, the CO oxidation was catalyzed with reaction rates of 0.676 and 0.206 molCO h−1 gPt−1 at 25 °C and 0 °C, respectively, under the O2-rich conditions (O2 : CO ratio of 66.7). These are record rates in the literature for Pt-based catalyst application for low-temperature CO oxidation under near atmospheric conditions.

DOI： 10.1039/d2cy00677d

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担当区分：最終著者,　責任著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Catalysis  

For the design of a high-performance platinum group metal-free three-way catalyst, we propose a new C3H6-preferential oxidation (C3H6-PROX) catalyst under stoichiometric automobile exhaust gas (NO–CO–C3H6–O2) using supported vanadia catalysts. Among various V2O5 supported catalysts, V2O5/TiO2 (anatase, coverage of around one monolayer) showed the best activity for C3H6-PROX with preferable formation of CO. The tandem catalyst combination using V2O5/TiO2 as the upstream C3H6-PROX catalyst and Cu/CeO2 as the downstream NO–CO reaction catalyst showed comparable activity for NO reduction as a Rh/ZrO2 catalyst. The reaction mechanism of C3H6 oxidation was analyzed using in situ Infrared spectroscopy. The C3H6 oxidation progressed with the formation of surface acetate as an intermediate, and acetate consumption was the key step of C3H6 oxidation. It is suggested that the Brønsted acid promoted the cleavage of the C–C bond of acetate, therefore, the number of Brønsted acid sites is one of the critical factors for the higher performance of C3H6-PROX catalysts.

DOI： 10.1016/j.jcat.2022.03.012

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsomega.1c06208

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.apcata.2021.118425

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Science and Technology  

Iron-containing zeolites possess active sites capable of catalyzing the low-temperature partial oxidation of methane using hydrogen peroxide as an environmentally benign oxidant. However, only a trace number of active sites have been found in zeolites so far. The high turnover frequency was limited to low loading samples, resulting in an upper limit of ∼50 mmol gcat−1 h−1 yield of C1 oxygenates. In this study, we synthesized a ZSM-5 catalyst containing a high concentration of single Fe sites with a high turnover frequency, and achieved a conversion of methane to C1 oxygenates of ∼200 mmol gcat−1 h−1 yield. It was important to use ZSM-5 as a carrier, which can be synthesized by hydrothermal treatment of aluminosilicate gel containing only tetra-propyl ammonium cations as the structure-directing agent (SDA). This ZSM-5 carrier has a large fraction of local environments possessing the nearest framework AlO4 tetrahedra required for the fixation of Fe cations in the mononuclear state while suppressing the co-generation of oligomeric Fe sites, making it possible to design a reaction field for the highly efficient partial oxidation of methane. The findings in the present study clearly showed that the fraction of single Fe cations and the Al distribution in the zeolite matrix are powerful activity descriptors for this class of materials. Furthermore, Al-distribution modification based on previously-established protocols, i.e., rational choice of an SDA used in the zeolite synthesis, is a meaningful way to tune not only the fabrication efficiency of single Fe cations but also the catalytic performance of Fe/ZSM-5 catalysts.

DOI： 10.1039/d1cy01987b

Web of Science

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physical Chemistry C  

Noble gas (Ng) elements are stable because of their octet electronic configuration, and thus Ng capture and purification are highly challenging. Here, we show a new concept for these applications: an orbital trap for Xe. This concept was found in Xe adsorption/separation processes at room temperature (RT) at the single Ag(I) site in MFI zeolite. Experiments and calculations showed the zeolite lattice-coordinated Ag(I) single ion has excellent electron-accepting nature and thereby induces the Xe 5p → Ag(I) 5s donation orbital interaction, forming a stable σ-bond with Xe even in the lower-pressure region and at RT. By contrast, the stable σ-bond for Kr adsorption is not established at RT because of the instability of the orbital interactions of the Kr 4p → Ag(I) 5s donation, as reflected from the relatively high energy of the Kr 4p orbital. Thus, the single Ag(I) site allows it to distinguish between Xe and Kr at RT; the Xe separation from the Xe/Kr gas mixture was achieved at RT using the Ag/MFI containing a high concentration of single Ag(I) sites. Our findings suggest that the orbital Xe trap using the local structure of porous materials shows promise as an efficient approach to selectively collect Xe (air concentration 0.087 ppm only). It will help to expand the range of applications of the costly Xe.

DOI： 10.1021/acs.jpcc.2c01515

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acs.jpcc.1c06760

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acsanm.1c00128

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ROYAL SOC CHEMISTRY  

Pd/Al2O3 catalysts were prepared using various Al2O3 supports with different structural features such as crystalline phase and crystallinity related to Al3+ coordination, revealing a significant insight into the methane (CH4) combustion activity of Pd nanoparticles with the fraction of penta-coordinated Al3+ sites in the Al2O3 supports.

DOI： 10.1039/d1cy00098e

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：American Chemical Society (ACS)  

DOI： 10.1021/acs.jpcc.1c01042

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1627/jpi.64.166

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/d0cy01989e

Web of Science

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jcat.2020.11.006

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/d0cy01294g

Web of Science

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physical Chemistry Letters  

Isolation of the atomic O radical anion bound to a metal ion (metal-oxyl) on solid surfaces is highly desirable for an understanding of how we should design the surface structure for using oxyl as the reactive site. Owing to the analytical difficulty of oxyl, however, even identification of oxyl remains scarce. Herein, we report isovalent ZnII-oxyl and GaIII-oxyl bonds isolated in the zeolite matrix. Close similarities in reactivity, spectroscopic property, and bonding nature were observed between them, but their site requirements were entirely different; the former is generated at the monovalent ion-exchangeable site, whereas the latter at the divalent ion-exchangeable site. This study strongly suggests that tuning the polarization of the metal-oxygen bond using the charge-controlled lattice oxygens is a useful way to constrain surface metal-oxyl bonds.

DOI： 10.1021/acs.jpclett.0c02980

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acscatal.0c03425

Web of Science

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/CL.200856

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担当区分：最終著者,　責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1021/acscatal.0c02050

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Today  

One-pot conversion of biomass derived 5-hydroxymethylfurfural (HMF) to 1,2,6-hexanetriol (1,2,6-HT) in water solvent was performed using Pt catalysts supported on various acid-base metal oxides. Pt catalysts supported on hydrotalcite, MgO, and CeO2 showed better yield of 1,2,6-HT and 2,5-bis(hydroxymethyl)-tetrahydrofuran (BHF), while ring-rearranged cyclopentanol derivatives were predominant products on the other Pt catalysts. The product distribution with time course on Pt/hydrotalcite revealed that HMF is at first hydrogenated to BHF, then the following parallel reactions proceed; ring-rearrangement to cyclopentanol derivatives, ring-hydrogenation to BHF, and hydrogenolysis to 1,2,6-HT. When pure hydrotalcite, MgO and CeO2 were physically mixed with Pt/SiO2, the selectivity to 1,2,6-HT was almost zero or less than 10 %. It was suggested that the formation of 1,2,6-HT proceeds at metal-support interface. The effect of metal-support interface was examined by means of IR spectra of adsorbed methanol. It was indicated that both basic property of supports and surface monodentate alkoxide formation are essential for the production of 1,2,6-HT. The maximum yield of 1,2,6-HT (42 %) was obtained using Co-promoted Pt/CeO2 catalysts pre-reduced at 200 °C.

DOI： 10.1016/j.cattod.2019.12.002

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Science and Technology  

One of the problems in a diesel oxidation catalyst is its insufficient activity for injected diesel fuel at low temperatures caused by strong adsorption of hydrocarbons. This study systematically clarified the poisoning effect of various hydrocarbons having carbon numbers from 3 to 16. As the carbon number in alkanes increased, the light-off temperature over a Pt-Pd/Al2O3 catalyst gradually shifted to a lower temperature. While alkenes and aromatics showed an opposite trend, the light-off shifted to a higher temperature as the carbon number increased. In situ FTIR spectra indicated that the amount of adsorbed hydrocarbons on the metal surface increased with the increase in the carbon number of alkanes and alkenes. Kinetic analysis showed that the reaction orders with respect to O2 were below zero in light alkane combustion, while those with respect to hydrocarbons were zero or lower in alkene and aromatic combustion. The shift of the light-off temperatures was rationalized by competitive adsorption of hydrocarbons and oxygen. This journal is

DOI： 10.1039/d0cy00017e

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Applied Materials and Interfaces  

Carbon monoxide (CO) molecules are attracting attention as capping agents that control the structure of metal nanoparticles. In this study, we aimed to control the shape and surface structure of Pd particles by reducing the supported Pd precursor with CO. The reduction of Pd nanoparticles with CO promoted the exposure of step sites and generated spherical and concave-tetrahedral Pd particles on carbon and SiO2 supports. On the other hand, conventional H2-reduced Pd particles show a flattened shape. The preferential exposure of the step sites by the adsorbed CO molecules was supported by the density functional theory-calculated surface energy and the Wulff construction. Morphology- and surface-controlled Pd nanoparticles were used to study the surface structure and morphology effects of Pd nanoparticles on cinnamaldehyde (CAL) hydrogenation. With an increase in the fraction of step sites on Pd nanoparticles, the hydrogenation activity and selectivity of hydrocinnamaldehyde (HCAL) increased. On step sites, the adsorption of the C-C bond of CAL proceeded preferentially, and HCAL was efficiently and selectively generated.

DOI： 10.1021/acsami.0c05938

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ChemCatChem  

The selective catalytic reduction of NO with ammonia (NH3−SCR) catalyzed by Cu−CHA zeolites is thoroughly investigated using in situ spectroscopic experiments combined with on-line mass spectroscopy (MS) under steady-state NH3−SCR conditions and transient conditions for Cu(II)/Cu(I) redox cycles. Quantitative analysis of the in situ XANES spectra of Cu−CHA under steady-state conditions of NH3−SCR show that NH3-coordinated Cu(II) species is the dominant Cu species at low temperatures (100–150 °C). At higher temperatures, Cu(II) species and [Cu(NH3)2]+ complex coexist, possibly because the rate of the Cu(II)→Cu(I) reduction step is comparable to that of the Cu(I)→Cu(II) oxidation step. In situ XANES, IR/MS, and UV-vis/MS experiments on the reduction half cycle demonstrate that the reduction of Cu(II) species occurs via the reaction of NH3-liganded Cu(II) with NO to yield N2 and H2O. For the oxidation half cycle, in situ XANES experiments of Cu(I) oxidation in 10 % O2 at 200 °C indicate that an increased density in CHA zeolite exhibits a higher oxidation rate. In situ UV-vis experiments of Cu(I) reoxidation using different mixtures of oxidant feed gas demonstrate the key role of O2 in the oxidation cycle. It is suggested that the reoxidation of Cu(I) to Cu(II) species occurs with only O2 as the oxidant, and a high Cu density in CHA zeolite promotes SCR activity by enhancing the oxidative activation of Cu(I) to Cu(II) during the catalytic cycle.

DOI： 10.1002/cctc.202000024

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Applied Materials and Interfaces  

Anion exchange membrane fuel cells (AEMFCs) are being developed for practical use. However, it is necessary to improve the hydrogen oxidation reaction (HOR) under alkaline conditions to enhance the performance of AEMFCs. In this study, carbon-supported Ru-Ir alloy nanoparticle catalysts (Ru-Ir/C) were developed because they offer higher HOR activity compared with the Pt-based catalysts. The mechanism of HOR enhancement on Ru-Ir/C was studied to reveal the effect of the surface composition of Ru/Ir on the HOR activity. The results showed that the HOR activity is related to the surface pair probability of Ru-Ir, Ru-Ru, and Ir-Ir but not to the hydrogen binding energy (HBE). In addition, the Ru-Ir pair site was found to be highly active, which can promote the HOR through a bifunctional mechanism that involves Ru-Ir pairs providing reactive OH- and H species, respectively.

DOI： 10.1021/acsami.0c00506

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Applied Energy Materials  

Anion exchange membrane fuel cells (AEMFCs) have been developed to the extent that the cell performance is nearing that of conventional proton exchange membrane fuel cells. For further improvement of AEMFC cell performance, it is necessary to develop the catalysis of hydrogen oxidation reactions (HORs) under basic conditions at the anode. Here, significant poisoning of Pt/C under basic conditions is demonstrated by electrochemical active surface area (ECSA) analysis using not only electrochemical measurement but also in situ Pt L3-edge X-ray adsorption spectroscopy (XAS). Furthermore, the in situ XAS analysis reveals that the surface modification of Pt/C with another metal species improves the ECSA of the Pt nanoparticles by removal of the surface poisoning, which contributes to the enhanced HOR performance of the modified Pt/C catalysts. Therefore, the removal of poisoning is proposed as a mechanism for improving the HOR on Pt-based catalysts.

DOI： 10.1021/acsaem.9b02274

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Today  

The modification of Cu-exchanged zeolites with phosphorus represents a promising method to enhance their hydrothermal stability, which is of pivotal importance for catalysts that promote the selective catalytic reduction of NO with ammonia (NH3–SCR). In this study, we investigated the reaction mechanism of NH3–SCR catalyzed by a phosphorus-modified CHA zeolite that contains active Cu species (Cu-P-CHA), and assessed the effect of the phosphorus modification on the hydrothermal stability of the catalyst by employing in situ/operando spectroscopic methods. In their entirety, the combined results from in situ/operando IR, UV–vis, and XANES experiments revealed that the NH3–SCR process over Cu-P-CHA proceeds via the reduction of Cu(II) to Cu(I) followed by a reoxidation of Cu(I) to Cu(II). In addition, we found that the phosphorus modification improved the hydrothermal durability of the catalyst by retaining a higher amount of the redox-active Cu species and the zeolite framework.

DOI： 10.1016/j.cattod.2020.07.084

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Catalysis  

The redox properties of supported Pd catalysts can directly affect their methane combustion activity. Here, the effect of the support on methane combustion was elucidated using Pd nanoparticles supported on various metal oxides (θ-Al2O3, γ-Al2O3, ZrO2, CeO2, MgO, La2O3, TiO2, SnO2, and Nb2O5). To eliminate the effect of Pd particle size and morphology, uniform Pd particles were synthesized in the liquid phase. Interestingly, the methane combustion activity formed a volcano plot when plotted against the oxide formation enthalpy (ΔfHM-O°) of the support. Combining X-ray photoelectron spectroscopy and scanning transmission electron microscopy-electron energy loss spectroscopy, the structure of the Pd nanoparticles on the support in an oxidizing atmosphere was identified. Pd particles on θ-Al2O3, γ-Al2O3, ZrO2, and CeO2 with moderate ΔfHM-O° adopted a metal-core-oxide-shell structure and showed the highest activities for methane combustion. In contrast, completely oxidized Pd particles were present on MgO and La2O3, which have lower ΔfHM-O° and were not very active. Pd metal particles on TiO2, SnO2, and Nb2O5 with higher ΔfHM-O° were not effective catalysts for methane combustion.

DOI： 10.1021/ACSCATAL.9B04524

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Science and Technology  

Gas-phase synthesis of morphology-controlled Pt nanoparticles (PtNPs) is conducted with carbon monoxide as a protective agent. Depending on the preparation temperature, Pt nanocubes with Pt{100} or cuboctahedra with Pt{111} and Pt{100} facets are formed by reducing Pt/C and Pt/SiO2 under a CO/H2 flow, although Pt nanospheres are formed under a H2 flow in the absence of CO. The influence of the Pt nanoparticle morphology on cinnamaldehyde hydrogenation is explored by comparing the hydrogenation performances of Pt nanocubes, cuboctahedrons, and spheres with various particle sizes. The hydrogenation activity and selectivity toward cinnamyl alcohol are enhanced in the order Pt nanocuboctahedra > Pt nanocubes > Pt nanospheres; thus, Pt{111} facets > Pt{100} facets > rounded (stepped) surface with respect to the surface structure.

DOI： 10.1039/c9cy00158a

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Catalysis  

We developed a high-performance PGM-free three-way catalyst based on a new strategy: a combination of two base-metal oxide catalysts with tandem configuration for hydrocarbon preferential oxidation (PROX) in upstream of exhausted gas and efficient purification of NO by CO in the downstream flow. The effectiveness of the tandem concept is verified by a combination of ZnCr2O4 for C3H6-PROX and CuCo2O4 for NO-CO-O2 reaction. The combination achieved a comparable performance to a Rh/ZrO2 catalyst, in terms of NO conversion (66.9%) and a superior performance regarding N2 yield (59.9%) and N2 selectivity (89.8%) at 300 °C.

DOI： 10.1021/acscatal.9b00526

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Communications  

To enhance the hydrogen oxidation reaction (HOR) activity of Pt/C under alkaline conditions, the catalyst's surface was modified with fifteen metals. The surface modification enhanced the activity of Pt/C for the HOR beyond a change in hydrogen binding energy (HBE), and this can be attributed to a change in the reactivity of surface oxygen species to adsorbed hydrogen species.

DOI： 10.1039/c9cc00582j

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ECS Transactions  

The cell performance of anion exchange membrane fuel cells (AEMFCs) has been getting closer to that of proton exchange membrane fuel cells (PEMFCs) by improvement of hydrogen oxidation reaction (HOR) catalysts on anodes with the help of the state-of-the-art AEMs having high ion conductivity. However, development of the alkaline HOR catalysts is still demanded to reduce the usage of precious metals on AEMFC anode. Here, Pt/C catalyst is modified to improve the HOR activity using fifteen metals on the group 4-11 of the 4th and 5th period in the periodic table except for Tc, i.e., Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Rh, Pd, Ag. In addition, the hydrogen binding energy of modified Pt/C and the oxophilicity of modifying metals are evaluated to reveal the mechanism of improved/lowered HOR activity.

DOI： 10.1149/09208.0733ecst

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis  

In situ and operando analyses are the methods to observe the real features of catalysts under the reaction conditions. These methods can clarify the dynamics of active species of catalysts and reaction scheme on catalyst surface through transient response method, kinetic study, temperature dependence of catalysts and products, and so on. In this review, progress in in situ and operando analyses is summarized with emphasis on environmental catalysts, i.e., catalysts for combustion, selective reduction of NO, automotive three-way catalysis, and related materials.

DOI： 10.1039/9781788016971-00242

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemistry - A European Journal  

Spinel-type NiFe2O4 exhibited the highest NO reduction activity among base-metal oxides under simulated exhaust of a gasoline-powered vehicle. The structure–activity relationship of iron oxides has been investigated through both experimental and computational studies. Spinel iron oxide (γ-Fe2O3) exhibited a much higher NO reduction activity than that of iron oxide with other structures (α-Fe2O3 and LaFeO3). Operando IR measurements clarified that the spinel structure facilitated the reaction between NOx and adsorbed oxidized hydrocarbon or cyanide species. The high reactivity of the spinel structure was ascribed to the high adsorption energy of NO, as elucidated by DFT calculations. Furthermore, molecular orbital calculations demonstrated that the local coordination structure of the spinel iron oxide induced the involvement of not only σ but also π orbitals during NO adsorption on Fe atoms. This work clarified the origin of the structure-dependent activity of metal oxides, with a focus on their local coordination structures.

DOI： 10.1002/CHEM.201902994

Web of Science

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemistry Letters  

The particle shape of a Pt/C catalyst is confined to octahedral by adding ethylene in an H2 stream during reduction of Pt/C. The Pt nano-octahedra enclosed by Pt{111} show higher catalytic activity for selective C=O hydrogenation of cinnamaldehyde in comparison with Pt nano-cuboctahedron, cube, and sphere.

DOI： 10.1246/CL.190462

Web of Science

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physical Chemistry C  

A supported Cu-based catalyst is designed for nitrogen oxide (NO) reduction reaction based on the previous exploration of Cu-M alloy nanoparticles by quantum chemical computations, where Cu-shell-Ru-core with incoherent interphase interfaces have been suggested as a candidate structure improving NO reduction activity. Here, such Cu-Ru nanoparticles are actually prepared in Al2O3-supported form by using electrostatic adsorption method as an adequate preparation method of supported core-shell alloy nanoparticle catalysts. Improved NO reduction activity by Cu-shell-Ru-core nanoparticles is demonstrated by NO-CO reaction activity tests on their Cu0/Ru surface in comparison to monometal surface of Cu and Ru nanoparticles.

DOI： 10.1021/ACS.JPCC.9B03687

Web of Science

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physical Chemistry Chemical Physics  

The active sites of Pd/Al2O3 catalysts for CO oxidations were identified by investigating the dependence of CO oxidation activities on the surface structure and morphology of Pd nanoparticles. The maximum catalytic activity was obtained for Pd particles approximately 2 nm in particle size. We performed structural analyses on the Pd surface through infrared (IR) spectroscopy of the adsorbed CO molecules. A positive correlation was obtained between catalytic activity and the fraction of linear CO adsorbed on Pd corner sites and Pd(111) facets, indicating that these sites are highly active for CO oxidation. X-ray absorption fine structure (XAFS) and spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) measurements demonstrated that Pd nanoparticles less than 2 nm in particle size with amorphous-like structures and Pd particles with large, well-ordered structures favor the formation of a high fraction of corner sites and Pd(111) facets, respectively.

DOI： 10.1039/C9CP03943K

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Microscopy  

In this article, we demonstrate that a convolutional neural network (CNN) can be effectively used to determine the presence of twins in the atomic resolution scanning transmission electron microscopy (STEM) images of catalytic Au nanoparticles. In particular, the CNN screening of Hough transformed images resulted in significantly higher accuracy rates as compared to those obtained by applying this technique to the raw STEM images. The proposed method can be utilized for evaluating the statistical twining fraction of Au nanoparticles that strongly affects their catalytic activity.

DOI： 10.1093/jmicro/dfy036

Web of Science

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemical Record  

Supported bimetallic catalysts have been studied because of their enhanced catalytic properties due to metal-metal interactions compared with monometallic catalysts. We focused on galvanic deposition (GD) as a bimetallization method, which achieves well-defined metal-metal interfaces by exchanging heterogeneous metals with different ionisation tendencies. We have developed Ni@Ag/SiO2 catalysts for CO oxidation, Co@Ru/Al2O3 catalysts for automotive three-way reactions and Pd−Co/Al2O3 catalysts for methane combustion by using the GD method. In all cases, the catalysts prepared by the GD method showed higher catalytic activity than the corresponding monometallic and bimetallic catalysts prepared by the conventional co-impregnation method. The GD method provides contact between noble and base metals to improve the electronic state, surface structure and reducibility of noble metals.

DOI： 10.1002/tcr.201700084

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ChemCatChem  

The highly active species of Pd/Al2O3 catalysts for methane combustion was revealed by in situ time-resolved dispersive X-ray absorption fine structure (DXAFS) spectroscopy. By using CH4 as a reduction agent, PdO in Pd/Al2O3 is reduced in a 2-step model involving Pd0 nucleation and growth of Pd0 domain in a PdO particle. Kinetic analysis of the 2-step model reduction of PdO nanoparticles leads to a suggestion that partial formation of Pd0 in a PdO particle accelerates methane combustion.

DOI： 10.1002/cctc.201800573

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley Blackwell  

A series of ceria-supported Rh nanoparticles (NPs) that have various particle sizes of 2–7 nm was prepared to investigate the size effect of Rh NPs on NO reduction in NO–CO–C3H6–O2 under stoichiometric conditions. The turnover frequency (TOF) for NO reduction on Rh NPs increased drastically according to their particle size. The strong size dependence of the TOF was attributed to the oxidation states of Rh NPs but not to particle geometries, which include fractions of surface local sites (e.g., corner, edge, plane) and the surface crystal structures (e.g., Rh(1 1 1), (1 0 0)). The variation of the TOF with the Rh metal fraction suggested that Rh metal ensembles are highly active species for NO reduction.

DOI： 10.1002/cctc.201701842

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Elsevier B.V.  

The NOx reduction activity of NiFe2O4 in automotive three-way catalysis was enhanced by physical mixing with CeO2, MgO, ZrO2, and Al2O3, while the mixing with TiO2 and Nb2O5 did not promoted the catalytic activity. On both pure NiFe2O4 and the physically mixed catalysts, NO was mainly reduced by C3H6 under the NO-C3H6-CO-O2 reaction conditions, because the temperature dependence of NO conversion in NO-C3H6-CO-O2 reaction was the same as that in NO-C3H6-O2 reaction. The in-situ FT/IR measurement revealed that the NO reduction proceeded with (1) partial oxidation of C3H6 to surface carboxylates, i.e., acetate and formate as good reductants for NO, and (2) reduction of NO by surface carboxylates. The metal oxide additives did not have catalytic activity for partial oxidation of C3H6 nor for NO oxidation to NO2, except CeO2. The main promotion effect was attributed to storage and release of surface carboxylates by metal oxide additives.

DOI： 10.1016/j.cattod.2017.07.026

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley Blackwell  

We report herein the first general catalytic system for the direct synthesis of N-substituted γ- and δ-lactams by reductive amination/cyclization of keto acids (including levulinic acid) with nitriles and H2 under mild conditions (7 bar H2, 110 °C, solvent free). The most effective catalyst, Pt and MoOx co-loaded TiO2 (Pt-MoOx/TiO2), shows a wide substrate scope, high turnover number (TON), and good reusability.

DOI： 10.1002/cctc.201701355

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/978-981-10-5137-1_5

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Angewandte Chemie - International Edition  

The particle size effect of Pd nanoparticles supported on alumina with various crystalline phases on methane combustion was investigated. Pd/θ, α-Al2O3 with weak metal-support interaction showed a volcano-shaped dependence of the catalytic activity on the size of Pd particles, and the catalytic activity of the strongly interacted Pd/γ-Al2O3 increased with the particle size. Based on a structural analysis of Pd nanoparticles using CO adsorption IR spectroscopy and spherical aberration-corrected scanning/transmission electron microscopy, the dependence of catalytic activity on Pd particle size and the alumina crystalline phase was due to the fraction of step sites on Pd particle surface. The difference in fraction of the step site is derived from the particle shape, which varies not only with Pd particle size but also with the strength of metal–support interaction. Therefore, this interaction perturbs the particle size effect of Pd/Al2O3 for methane combustion.

DOI： 10.1002/anie.201709124

Web of Science

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：CHEMICAL SOC JAPAN  

We studied the dynamic redox behavior of Cu species in zeolite matrix under NH3-SCR using in situ XAFS. Cu2+ species were slowly reduced to Cu+ in flowing NH3, and subsequent addition of NO promoted the reduction to Cu+. In the oxidation step, oxygen alone did not fully oxidize Cu+ to Cu2+, but the Cu+ species were completely oxidized to Cu2+ by NO-O-2. The oxidation step was slower than the reduction step, which suggested that the oxidation step (Cu+ -> Cu2+) is the slow step of the NH3-SCR reaction.

DOI： 10.1246/cl.170451

Web of Science

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Omega  

To elucidate the reaction mechanism of NO-C3H6-CO-O2 over NiFe2O4, we investigated the dynamics of the adsorbed and gaseous species during the reaction using operando Fourier transform infrared (FTIR). The NO reduction activity dependent on the C3H6 and CO concentrations suggested that NO is reduced by C3H6 under three-way catalytic conditions. From FTIR measurements and kinetic analysis, it was clarified that the acetate species reacted with NO-O2 to form N2 via NCO, and that the rate-limiting step of NO reduction was the reaction between CH3COO- and NO-O2. The NO reduction mechanism of the three-way catalyst on NiFe2O4 is different to that on platinum-group metal catalysts, on which NO reduction proceeds through N-O cleavage.

DOI： 10.1021/acsomega.7b00165

Web of Science

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記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ChemCatChem  

Glucose isomerization was performed using various titanate catalysts, which include SrTiO3, BaTiO3, CaTiO3, Na2Ti6O13, K2Ti6O13, and Sr3Ti2O7, prepared using a conventional solid-phase method. Among the titanates, SrTiO3, CaTiO3, and Na2Ti6O13 offered a relatively high fructose yield (32 %) with a high selectivity (68–78 %). The yields are comparable to yields reported previously using a Sn-modified BEA zeolite, which shows a high efficiency for glucose isomerization as a Lewis acid catalyst. A study of the mechanism of glucose isomerization on a SrTiO3 catalyst surface by using 1H NMR spectroscopy suggested that the titanates catalyze the isomerization as base catalysts. Thus, the effect of the basicity of the titanates on glucose isomerization was investigated in terms of the base quantity and strength. The analysis was performed by using an acid–base titration method and FTIR spectroscopy with CHCl3 as a probe molecule. It is proposed that glucose isomerization on the titanates depends not only on the base amount but also on the base strength.

DOI： 10.1002/cctc.201700068

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ROYAL SOC CHEMISTRY  

Combination catalyst systems composed of Pt/SiO2 and lanthanoid oxides (Pt/SiO2 + LOx) efficiently catalyze the hydrogenative ring-rearrangement of 5-(hydroxymethyl) furfural (HMF) in water to produce 3-(hydroxymethyl) cyclopentanol (HCPO), which can be a unique building block for new materials derived from biomass. We investigated the reason for the efficient hydrogenative ring-rearrangement on Pt/SiO2 + LOx in terms of the acid-base properties of reaction systems, since H+ and Lewis acids can affect the rearrangement of the furan ring. It is indicated that the ring-rearrangement efficiently proceeds under slightly acidic conditions (pH = 5-7) with moderate or a little weak Lewis acidity of lanthanoid oxides.

DOI： 10.1039/c7cy00712d

Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysts  

Recently, it has been reported that the morphology of Au nanoparticles (NPs) affects the catalytic activity of CO oxidation; twin crystal NPs show higher activity for CO oxidation than single-crystal NPs. In this study, density functional calculations have been carried out to investigate the morphology effect of Au NPs using CO as a probe molecule. In the case of Au NPs with a size of more than 2 nm, CO adsorption energy on the Au NPs is mainly determined by a coordination number (CN) of adsorption sites. CO binding to a multiple twin NP with a size of about 1 nm is stronger than that on a single-crystal NP with the same size. A simple CN explanation cannot be applied to the enhancement of CO binding to the small multiple twin NP. This enhancement is related to a deformation of the NP structure before and after CO adsorption. It is suggested that the multiple twin NP with a size of less than 1 nm, which shows the deformation upon CO adsorption, contributes to the higher activity for CO oxidation.

DOI： 10.3390/catal7060191

Web of Science

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：RSC Advances  

Pd/CoAl2O4/Al2O3 methane combustion catalysts were synthesized using a galvanic deposition (GD) method (PdCoAl-GD). This PdCoAl-GD catalyst showed higher activities and turnover frequencies (TOFs) than conventional Pd/Al2O3. According to X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and scanning transmission electron microscopy (STEM) measurements, PdCoAl-GD was composed of a CoAl2O4 phase supported on γ-Al2O3 and dispersed Pd nanoparticles of 2-7 nm in size on CoAl2O4. Operando Pd K-edge XAFS measurements indicated that the Pd in PdCoAl-GD was oxidized to highly active methane combustion PdO species at low temperatures. PdCoAl-GD also showed high activity (light-off tests) when PdO was initially present on the catalysts. Methane temperature-programmed reaction (CH4-TPR) measurements on PdCoAl-GD revealed that PdO was reduced by CH4 at low temperatures. The GD method used herein achieved PdO species that were effective for C-H activation.

DOI： 10.1039/c7ra06150a

Web of Science

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Chemistry Letters  

We studied the dynamic redox behavior of Cu species in zeolite matrix under NH3-SCR using in situ XAFS. Cu2+ species were slowly reduced to Cu+ in flowing NH3, and subsequent addition of NO promoted the reduction to Cu+. In the oxidation step, oxygen alone did not fully oxidize Cu+ to Cu2+, but the Cu+ species were completely oxidized to Cu2+ by NOO2. The oxidation step was slower than the reduction step, which suggested that the oxidation step (Cu+ ¼ Cu2+) is the slow step of the NH3-SCR reaction.

DOI： 10.1246/cl.170451

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Catalysis Science and Technology  

Combination catalyst systems composed of Pt/SiO2 and lanthanoid oxides (Pt/SiO2 + LOx) efficiently catalyze the hydrogenative ring-rearrangement of 5-(hydroxymethyl)furfural (HMF) in water to produce 3-(hydroxymethyl)cyclopentanol (HCPO), which can be a unique building block for new materials derived from biomass. We investigated the reason for the efficient hydrogenative ring-rearrangement on Pt/SiO2 + LOx in terms of the acid-base properties of reaction systems, since H+ and Lewis acids can affect the rearrangement of the furan ring. It is indicated that the ring-rearrangement efficiently proceeds under slightly acidic conditions (pH = 5-7) with moderate or a little weak Lewis acidity of lanthanoid oxides.

DOI： 10.1039/c7cy00712d

Scopus

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：COMODIA 2017 - 9th International Conference on Modeling and Diagnostics for Advanved Engine Systems  

DPF (Diesel Particulate Filter) is effective for trapping diesel soot from diesel engines. The trapped diesel soot is removed by combustion above 600°C using excess fuels, which results in reduction of fuel economy. An effective design of DPF is strongly required to improve DPF regeneration efficiency and fuel economy; however, the internal phenomenon of diesel soot combustion on DPF is still not clarified. For an effective design of DPF, in this study, we investigated the effect of diesel soot structure on combustion temperature using real diesel soot. Soot samples were characterized by means of various physicochemical techniques: XPS (X-ray photoelectron spectroscopy), EELS (Electron Energy Loss Spectroscopy), Raman spectroscopy, TEM (transmission electron microscopy), and elemental analysis. TEM images and Raman spectra of real diesel soot showed that the difference in the crystallinity of soot was small. XPS, EELS, and elemental analysis revealed that oxygen content, which is derived from surface functional groups of - COOH, -OH, and - C=O at defect sites, was strongly affected by the engine operating conditions. The ignition temperature of diesel soot was dependent on O/C ratio measured by elemental analysis. With the increase in oxygen content of diesel soot, combustion temperatures of soot became lower. It was concluded that the concentration of oxygen containing functional groups is an essential factor for the control of the ignition temperature of diesel soot.

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI: 10.1039/C6TA05517F

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI: 10.1039/c6cy00795c

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi.org/10.1246/bcsj.20160102

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI: 10.1016/j.cattod.2015.11.043

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI: 10.1016/j.jcat.2015.11.021

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： doi:10.1007/s10562-015-1658-5

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.cattod.2015.03.047

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/c5cc05484b

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/C5GC01723H

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/cl.150123

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/C4RA10167G

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.cattod.2014.05.046

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1246/cl.140165

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/C3CC49591D

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1007/s11244-014-0274-8

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/jmicro/dfu001

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jpowsour

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI: 10.1021/ja4021638

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： dx.doi.org/10.1021/cs4001267

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI: 10.1039/c3cy00033h

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI: 10.1016/j.apcatb.2012.12.025

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.cattod.2012.03.048

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： DOI: 10.1039/C2RA22190J

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.apcatb.2011.11.002

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1627/jpi.54.347

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/cctc.201100171

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/C1GC15835J

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/C1RA00560J

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1039/C0CY00077A

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The mechanistic cause of the dramatic activity improvement of alumina-supported silver (Ag/Al2O3)byH2 addition for the selective catalytic reduction of NO with propane (C3H8-SCR) was investigated by catalytic and spectroscopic studies. In situ UV-vis, in situ EXAFS, IR, and microcalorimetric experiments show that
H2 reduction of Ag+ ions on Ag/Al2O3 at 573 K yields protons on alumina and partially reduced Agn clusters, which are subsequently aggregated to larger Ag clusters. During H2 + O2 and H2-assisted C3H8-SCR reactions, Ag+ ions and Agn .+ coexist. Reoxidation with O2 results in the redispersion of the cluster to Ag+ ion, accompanying a reaction of protons. The relationship between cluster size, redox properties, and catalytic activity is examined using Ag/Al2O3 of different Ag loadings. The steady-state NO reduction rate correlates fairly well with the amount of Agn .+ during the H2-assisted C3H8-SCR reaction. It is shown that Agn .+ is the active species, whereas monomeric Ag+ ion and metallic Ag particles are inactive. With Ag loading, the Ag+ reduction rate increases and the rate of cluster reoxidation decreases. A balance between the rate of reduction and reoxidation of Ag species is an important factor that controls the size and oxidation state of the Ag species and consequently the catalytic activity of Ag/Al2O3. ESR has provided evidence, for the first time, for the in situ generation of superoxide ions in H2 + O2 and H2-assisted C3H8-SCR reactions. The comprehensive reason for the hydrogen effect in HC-SCR is discussed, focusing on the role of the cluster and protons on the reductive O2 activation to superoxide ion.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語  

記述言語：英語  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Selective catalytic reduction of NO by hydrocarbons (HC-SCR) is one of the promising technologies for removal of NO in exhausts containing excess oxygen, such as diesel and lean burn gasoline engines. Supported Ag catalysts, especially Ag/Al2O3, are thought to be the promising candidates for use in diesel exhausts, as con.rmed by several reports on engine bench tests. The HC-SCR performance of supported Ag catalysts is very sensitive to the reaction conditions, especially the type of hydrocarbons and the addition of H2. The control of reaction conditions would be key for practical use. The current research of supported Ag catalysts is reviewed from the viewpoints of practical use and the reaction mechanism, i.e., the reaction scheme, the role of surface adsorbed species, and the structure of active Ag species.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Involvement of active sites in the selective oxidation of propane was investigated using (VO)2P2O7 catalysts promoted by Sb, Ti, Zr, Hf, Cu, and Ce. Based on X-ray diffraction patterns, infrared spectra, and Raman spectra, the formation of a (VO)2P2O7 phase was con.rmed for all of the promoted catalysts; no other phases were detected. After the addition of Sb, Ti, and Zr, the selectivity to acrylic acid increased, whereas Cu-, Ce-, and Hf-promoted catalysts showed lower selectivity than pure (VO)2P2O7. The effect of promoters on the activity and selectivity for the propane oxidation was investigated on the basis of the nature of surface active sites. The surface V=O species, evaluated by the nitric oxide.ammonia rectangular pulse technique, decreased with the addition of the promoters. A proportional correlation between the number of surface V=O species and reaction rate of propane clari.ed that the surface V=O species is the controlling factor for the catalytic activity of propane oxidation. In the case of Sb-, Ti-, and Zr-promoted catalysts, the selectivity to acrylic acid increased signi.cantly. The selectivity was compared with the number and strength of Bronsted and Lewis acid sites estimated from dimethylpyridine temperature-programmed desorption. A good correlation was observed between the selectivity to acrylic acid and the surface concentration of Lewis acid sites. It was experimentally demonstrated that Lewis acid sites represent the key factor in selective oxidation.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語  

担当区分：筆頭著者   記述言語：日本語  

担当区分：筆頭著者   記述言語：英語  

担当区分：筆頭著者   記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Silver-alumina catalysts prepared by sol.gel method (Ag-Al2O3) and impregnation method (Ag/Al2O3) were studied for the selective catalytic reduction (SCR) of NO by higher alkanes (n-hexane and n-octane). UV.VIS and Ag K-edge XAFS results established the structure of the catalysts; below 2 wt.%, highly dispersed Ag+ ions are predominant Ag species, while at higher Ag loading, Agn clusters are predominant. A relationship between the structure of Ag species and their catalytic function for SCR by n-octane was clari.ed. Ag+ ions are responsible for the selective reduction of NO to N2, while the Agn clusters are responsible for the hydrocarbon combustion and N2O formation. The mechanism of SCR by n-hexane on Ag-Al2O3, which mainly consists of Ag+ ions, were investigated by in situ FTIR spectroscopy. During NO + n-hexane + O2 reaction, the acetate produced via the partial oxidation of n-hexane and the nitrates produced via the oxidation of NO were main adspecies in the steady-state condition at 473.623 K. The acetate, which was stable in O2 or NO, was reactive in NO+O2. Nitrates, which were relatively stable in n-hexane, were quite reactive toward n-hexane+O2. The rate of nitrates reaction in n-hexane+O2 was close to the steady-state rate of NO reduction over wide range of temperature, indicating that the nitrate is a possible intermediate in the SCR. A proposed mechanism, suggesting the reaction of nitrates with partially oxidized hydrocarbon species as a crucial step, explains the steady-state kinetic results. At relatively high NO concentration or at low temperature, nitrates should inhibit the reaction by strongly adsorbing on the catalyst surface.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語  

担当区分：筆頭著者   記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

総ページ数：12   担当ページ：75-86   記述言語：日本語 著書種別：学術書

一昨年に報道された排気ガス規制偽装の報道は記憶に新しいかと思われますが、ディーゼルエンジンの需要は新興国市場で伸び、また日本でも従来のイメージから脱却し、燃料代が安く、熱の効率が良いディーゼルエンジンがあらためて注目されています。欧米では日本と事情は異なりますがそれぞれ独自の需要と市場を形成しています。しかしながら各市場・規制が要求するレベルで排出ガスをクリーンにすることが最大の課題となっております。そこで弊社では排出ガス浄化技術においてキーマテリアルである触媒およびそのシステムの開発、要素技術に焦点をあてた書籍を発刊します。

記述言語：日本語

記述言語：日本語

記述言語：日本語

記述言語：日本語

記述言語：日本語

記述言語：日本語

担当ページ：5-10   記述言語：日本語

記述言語：英語

担当ページ：98-103  

担当ページ：98-103  

担当ページ：57-62  

記述言語：日本語

記述言語：日本語

担当ページ：60-66  

DOI： doi:10.20731/zeoraito.24.2.60

担当ページ： 544-548  

記述言語：日本語

担当ページ：64-65  

記述言語：日本語

記述言語：日本語

担当ページ：696-699  

担当ページ：35-37  

記述言語：日本語

DOI： doi:10.20731/zeoraito.18.2.58

担当ページ：57-58  

記述言語：日本語

記述言語：日本語

記述言語：日本語

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：Wiley Blackwell  

We report herein the first general catalytic system for the direct synthesis of N-substituted γ- and δ-lactams by reductive amination/cyclization of keto acids (including levulinic acid) with nitriles and H2 under mild conditions (7 bar H2, 110 °C, solvent free). The most effective catalyst, Pt and MoOx co-loaded TiO2 (Pt-MoOx/TiO2), shows a wide substrate scope, high turnover number (TON), and good reusability.

DOI： 10.1002/cctc.201701355

Scopus

J-GLOBAL

J-GLOBAL

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）  

DOI： 10.1007/978-981-10-5137-1_5

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：WILEY-V C H VERLAG GMBH  

The particle size effect of Pd nanoparticles supported on alumina with various crystalline phases on methane combustion was investigated. Pd/, -Al2O3 with weak metal-support interaction showed a volcano-shaped dependence of the catalytic activity on the size of Pd particles, and the catalytic activity of the strongly interacted Pd/-Al2O3 increased with the particle size. Based on a structural analysis of Pd nanoparticles using CO adsorption IR spectroscopy and spherical aberration-corrected scanning/transmission electron microscopy, the dependence of catalytic activity on Pd particle size and the alumina crystalline phase was due to the fraction of step sites on Pd particle surface. The difference in fraction of the step site is derived from the particle shape, which varies not only with Pd particle size but also with the strength of metal-support interaction. Therefore, this interaction perturbs the particle size effect of Pd/Al2O3 for methane combustion.

DOI： 10.1002/anie.201709124

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：WILEY-V C H VERLAG GMBH  

The particle size effect of Pd nanoparticles supported on alumina with various crystalline phases on methane combustion was investigated. Pd/, -Al2O3 with weak metal-support interaction showed a volcano-shaped dependence of the catalytic activity on the size of Pd particles, and the catalytic activity of the strongly interacted Pd/-Al2O3 increased with the particle size. Based on a structural analysis of Pd nanoparticles using CO adsorption IR spectroscopy and spherical aberration-corrected scanning/transmission electron microscopy, the dependence of catalytic activity on Pd particle size and the alumina crystalline phase was due to the fraction of step sites on Pd particle surface. The difference in fraction of the step site is derived from the particle shape, which varies not only with Pd particle size but also with the strength of metal-support interaction. Therefore, this interaction perturbs the particle size effect of Pd/Al2O3 for methane combustion.

DOI： 10.1002/anie.201709124

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：WILEY-V C H VERLAG GMBH  

The particle size effect of Pd nanoparticles supported on alumina with various crystalline phases on methane combustion was investigated. Pd/, -Al2O3 with weak metal-support interaction showed a volcano-shaped dependence of the catalytic activity on the size of Pd particles, and the catalytic activity of the strongly interacted Pd/-Al2O3 increased with the particle size. Based on a structural analysis of Pd nanoparticles using CO adsorption IR spectroscopy and spherical aberration-corrected scanning/transmission electron microscopy, the dependence of catalytic activity on Pd particle size and the alumina crystalline phase was due to the fraction of step sites on Pd particle surface. The difference in fraction of the step site is derived from the particle shape, which varies not only with Pd particle size but also with the strength of metal-support interaction. Therefore, this interaction perturbs the particle size effect of Pd/Al2O3 for methane combustion.

DOI： 10.1002/anie.201709124

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：CHEMICAL SOC JAPAN  

We studied the dynamic redox behavior of Cu species in zeolite matrix under NH3-SCR using in situ XAFS. Cu2+ species were slowly reduced to Cu+ in flowing NH3, and subsequent addition of NO promoted the reduction to Cu+. In the oxidation step, oxygen alone did not fully oxidize Cu+ to Cu2+, but the Cu+ species were completely oxidized to Cu2+ by NO-O-2. The oxidation step was slower than the reduction step, which suggested that the oxidation step (Cu+ -> Cu2+) is the slow step of the NH3-SCR reaction.

DOI： 10.1246/cl.170451

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：CHEMICAL SOC JAPAN  

We studied the dynamic redox behavior of Cu species in zeolite matrix under NH3-SCR using in situ XAFS. Cu2+ species were slowly reduced to Cu+ in flowing NH3, and subsequent addition of NO promoted the reduction to Cu+. In the oxidation step, oxygen alone did not fully oxidize Cu+ to Cu2+, but the Cu+ species were completely oxidized to Cu2+ by NO-O-2. The oxidation step was slower than the reduction step, which suggested that the oxidation step (Cu+ -> Cu2+) is the slow step of the NH3-SCR reaction.

DOI： 10.1246/cl.170451

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：American Chemical Society  

To elucidate the reaction mechanism of NO-C3H6-CO-O2 over NiFe2O4, we investigated the dynamics of the adsorbed and gaseous species during the reaction using operando Fourier transform infrared (FTIR). The NO reduction activity dependent on the C3H6 and CO concentrations suggested that NO is reduced by C3H6 under three-way catalytic conditions. From FTIR measurements and kinetic analysis, it was clarified that the acetate species reacted with NO-O2 to form N2 via NCO, and that the rate-limiting step of NO reduction was the reaction between CH3COO- and NO-O2. The NO reduction mechanism of the three-way catalyst on NiFe2O4 is different to that on platinum-group metal catalysts, on which NO reduction proceeds through N-O cleavage.

DOI： 10.1021/acsomega.7b00165

Scopus

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：American Chemical Society  

To elucidate the reaction mechanism of NO-C3H6-CO-O2 over NiFe2O4, we investigated the dynamics of the adsorbed and gaseous species during the reaction using operando Fourier transform infrared (FTIR). The NO reduction activity dependent on the C3H6 and CO concentrations suggested that NO is reduced by C3H6 under three-way catalytic conditions. From FTIR measurements and kinetic analysis, it was clarified that the acetate species reacted with NO-O2 to form N2 via NCO, and that the rate-limiting step of NO reduction was the reaction between CH3COO- and NO-O2. The NO reduction mechanism of the three-way catalyst on NiFe2O4 is different to that on platinum-group metal catalysts, on which NO reduction proceeds through N-O cleavage.

DOI： 10.1021/acsomega.7b00165

Scopus

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：American Chemical Society  

To elucidate the reaction mechanism of NO-C3H6-CO-O2 over NiFe2O4, we investigated the dynamics of the adsorbed and gaseous species during the reaction using operando Fourier transform infrared (FTIR). The NO reduction activity dependent on the C3H6 and CO concentrations suggested that NO is reduced by C3H6 under three-way catalytic conditions. From FTIR measurements and kinetic analysis, it was clarified that the acetate species reacted with NO-O2 to form N2 via NCO, and that the rate-limiting step of NO reduction was the reaction between CH3COO- and NO-O2. The NO reduction mechanism of the three-way catalyst on NiFe2O4 is different to that on platinum-group metal catalysts, on which NO reduction proceeds through N-O cleavage.

DOI： 10.1021/acsomega.7b00165

Scopus

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：WILEY-V C H VERLAG GMBH  

Glucose isomerization was performed using various titanate catalysts, which include SrTiO3, BaTiO3, CaTiO3, Na2Ti6O13, K2Ti6O13, and Sr3Ti2O7, prepared using a conventional solid-phase method. Among the titanates, SrTiO3, CaTiO3, and Na2Ti6O13 offered a relatively high fructose yield (32%) with a high selectivity (68-78%). The yields are comparable to yields reported previously using a Sn-modified BEA zeolite, which shows a high efficiency for glucose isomerization as a Lewis acid catalyst. A study of the mechanism of glucose isomerization on a SrTiO3 catalyst surface by using H-1 NMR spectroscopy suggested that the titanates catalyze the isomerization as base catalysts. Thus, the effect of the basicity of the titanates on glucose isomerization was investigated in terms of the base quantity and strength. The analysis was performed by using an acid-base titration method and FTIR spectroscopy with CHCl3 as a probe molecule. It is proposed that glucose isomerization on the titanates depends not only on the base amount but also on the base strength.

DOI： 10.1002/cctc.201700068

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：ROYAL SOC CHEMISTRY  

Combination catalyst systems composed of Pt/SiO2 and lanthanoid oxides (Pt/SiO2 + LOx) efficiently catalyze the hydrogenative ring-rearrangement of 5-(hydroxymethyl) furfural (HMF) in water to produce 3-(hydroxymethyl) cyclopentanol (HCPO), which can be a unique building block for new materials derived from biomass. We investigated the reason for the efficient hydrogenative ring-rearrangement on Pt/SiO2 + LOx in terms of the acid-base properties of reaction systems, since H+ and Lewis acids can affect the rearrangement of the furan ring. It is indicated that the ring-rearrangement efficiently proceeds under slightly acidic conditions (pH = 5-7) with moderate or a little weak Lewis acidity of lanthanoid oxides.

DOI： 10.1039/c7cy00712d

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：WILEY-V C H VERLAG GMBH  

Glucose isomerization was performed using various titanate catalysts, which include SrTiO3, BaTiO3, CaTiO3, Na2Ti6O13, K2Ti6O13, and Sr3Ti2O7, prepared using a conventional solid-phase method. Among the titanates, SrTiO3, CaTiO3, and Na2Ti6O13 offered a relatively high fructose yield (32%) with a high selectivity (68-78%). The yields are comparable to yields reported previously using a Sn-modified BEA zeolite, which shows a high efficiency for glucose isomerization as a Lewis acid catalyst. A study of the mechanism of glucose isomerization on a SrTiO3 catalyst surface by using H-1 NMR spectroscopy suggested that the titanates catalyze the isomerization as base catalysts. Thus, the effect of the basicity of the titanates on glucose isomerization was investigated in terms of the base quantity and strength. The analysis was performed by using an acid-base titration method and FTIR spectroscopy with CHCl3 as a probe molecule. It is proposed that glucose isomerization on the titanates depends not only on the base amount but also on the base strength.

DOI： 10.1002/cctc.201700068

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：WILEY-V C H VERLAG GMBH  

Glucose isomerization was performed using various titanate catalysts, which include SrTiO3, BaTiO3, CaTiO3, Na2Ti6O13, K2Ti6O13, and Sr3Ti2O7, prepared using a conventional solid-phase method. Among the titanates, SrTiO3, CaTiO3, and Na2Ti6O13 offered a relatively high fructose yield (32%) with a high selectivity (68-78%). The yields are comparable to yields reported previously using a Sn-modified BEA zeolite, which shows a high efficiency for glucose isomerization as a Lewis acid catalyst. A study of the mechanism of glucose isomerization on a SrTiO3 catalyst surface by using H-1 NMR spectroscopy suggested that the titanates catalyze the isomerization as base catalysts. Thus, the effect of the basicity of the titanates on glucose isomerization was investigated in terms of the base quantity and strength. The analysis was performed by using an acid-base titration method and FTIR spectroscopy with CHCl3 as a probe molecule. It is proposed that glucose isomerization on the titanates depends not only on the base amount but also on the base strength.

DOI： 10.1002/cctc.201700068

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：MDPI AG  

Recently, it has been reported that the morphology of Au nanoparticles (NPs) affects the catalytic activity of CO oxidation; twin crystal NPs show higher activity for CO oxidation than single-crystal NPs. In this study, density functional calculations have been carried out to investigate the morphology effect of Au NPs using CO as a probe molecule. In the case of Au NPs with a size of more than 2 nm, CO adsorption energy on the Au NPs is mainly determined by a coordination number (CN) of adsorption sites. CO binding to a multiple twin NP with a size of about 1 nm is stronger than that on a single-crystal NP with the same size. A simple CN explanation cannot be applied to the enhancement of CO binding to the small multiple twin NP. This enhancement is related to a deformation of the NP structure before and after CO adsorption. It is suggested that the multiple twin NP with a size of less than 1 nm, which shows the deformation upon CO adsorption, contributes to the higher activity for CO oxidation.

DOI： 10.3390/catal7060191

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：MDPI AG  

Recently, it has been reported that the morphology of Au nanoparticles (NPs) affects the catalytic activity of CO oxidation; twin crystal NPs show higher activity for CO oxidation than single-crystal NPs. In this study, density functional calculations have been carried out to investigate the morphology effect of Au NPs using CO as a probe molecule. In the case of Au NPs with a size of more than 2 nm, CO adsorption energy on the Au NPs is mainly determined by a coordination number (CN) of adsorption sites. CO binding to a multiple twin NP with a size of about 1 nm is stronger than that on a single-crystal NP with the same size. A simple CN explanation cannot be applied to the enhancement of CO binding to the small multiple twin NP. This enhancement is related to a deformation of the NP structure before and after CO adsorption. It is suggested that the multiple twin NP with a size of less than 1 nm, which shows the deformation upon CO adsorption, contributes to the higher activity for CO oxidation.

DOI： 10.3390/catal7060191

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：MDPI AG  

Recently, it has been reported that the morphology of Au nanoparticles (NPs) affects the catalytic activity of CO oxidation; twin crystal NPs show higher activity for CO oxidation than single-crystal NPs. In this study, density functional calculations have been carried out to investigate the morphology effect of Au NPs using CO as a probe molecule. In the case of Au NPs with a size of more than 2 nm, CO adsorption energy on the Au NPs is mainly determined by a coordination number (CN) of adsorption sites. CO binding to a multiple twin NP with a size of about 1 nm is stronger than that on a single-crystal NP with the same size. A simple CN explanation cannot be applied to the enhancement of CO binding to the small multiple twin NP. This enhancement is related to a deformation of the NP structure before and after CO adsorption. It is suggested that the multiple twin NP with a size of less than 1 nm, which shows the deformation upon CO adsorption, contributes to the higher activity for CO oxidation.

DOI： 10.3390/catal7060191

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：ROYAL SOC CHEMISTRY  

Pd/CoAl2O4/Al2O3 methane combustion catalysts were synthesized using a galvanic deposition (GD) method (PdCoAl-GD). This PdCoAl-GD catalyst showed higher activities and turnover frequencies (TOFs) than conventional Pd/Al2O3. According to X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and scanning transmission electron microscopy (STEM) measurements, PdCoAl-GD was composed of a CoAl2O4 phase supported on gamma-Al2O3 and dispersed Pd nanoparticles of 2-7 nm in size on CoAl2O4. Operando Pd K-edge XAFS measurements indicated that the Pd in PdCoAl-GD was oxidized to highly active methane combustion PdO species at low temperatures. PdCoAl-GD also showed high activity (light-off tests) when PdO was initially present on the catalysts. Methane temperature-programmed reaction (CH4-TPR) measurements on PdCoAl-GD revealed that PdO was reduced by CH4 at low temperatures. The GD method used herein achieved PdO species that were effective for C-H activation.

DOI： 10.1039/c7ra06150a

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：ROYAL SOC CHEMISTRY  

Pd/CoAl2O4/Al2O3 methane combustion catalysts were synthesized using a galvanic deposition (GD) method (PdCoAl-GD). This PdCoAl-GD catalyst showed higher activities and turnover frequencies (TOFs) than conventional Pd/Al2O3. According to X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and scanning transmission electron microscopy (STEM) measurements, PdCoAl-GD was composed of a CoAl2O4 phase supported on gamma-Al2O3 and dispersed Pd nanoparticles of 2-7 nm in size on CoAl2O4. Operando Pd K-edge XAFS measurements indicated that the Pd in PdCoAl-GD was oxidized to highly active methane combustion PdO species at low temperatures. PdCoAl-GD also showed high activity (light-off tests) when PdO was initially present on the catalysts. Methane temperature-programmed reaction (CH4-TPR) measurements on PdCoAl-GD revealed that PdO was reduced by CH4 at low temperatures. The GD method used herein achieved PdO species that were effective for C-H activation.

DOI： 10.1039/c7ra06150a

Web of Science

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）   出版者・発行元：ROYAL SOC CHEMISTRY  

Pd/CoAl2O4/Al2O3 methane combustion catalysts were synthesized using a galvanic deposition (GD) method (PdCoAl-GD). This PdCoAl-GD catalyst showed higher activities and turnover frequencies (TOFs) than conventional Pd/Al2O3. According to X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and scanning transmission electron microscopy (STEM) measurements, PdCoAl-GD was composed of a CoAl2O4 phase supported on gamma-Al2O3 and dispersed Pd nanoparticles of 2-7 nm in size on CoAl2O4. Operando Pd K-edge XAFS measurements indicated that the Pd in PdCoAl-GD was oxidized to highly active methane combustion PdO species at low temperatures. PdCoAl-GD also showed high activity (light-off tests) when PdO was initially present on the catalysts. Methane temperature-programmed reaction (CH4-TPR) measurements on PdCoAl-GD revealed that PdO was reduced by CH4 at low temperatures. The GD method used herein achieved PdO species that were effective for C-H activation.

DOI： 10.1039/c7ra06150a

Web of Science

開催年月日： 2021年3月

記述言語：日本語   会議種別：ポスター発表  

開催地：オンライン  

開催年月日： 2021年3月

記述言語：日本語   会議種別：ポスター発表  

開催地：オンライン  

開催年月日： 2020年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン  

開催年月日： 2020年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン  

開催年月日： 2020年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：熊本城ホール  

開催年月日： 2020年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：熊本城ホール  

開催年月日： 2020年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン  

開催年月日： 2020年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン  

開催年月日： 2020年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2020年9月

記述言語：日本語   会議種別：ポスター発表  

開催地：オンライン   国名：日本国  

開催年月日： 2020年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2019年11月

記述言語：英語   会議種別：口頭発表（基調）  

開催地：Yancheng, China   国名：日本国  

開催年月日： 2019年8月

記述言語：英語   会議種別：口頭発表（招待・特別）  

開催地：Lotte Hotel, Jeju, South Korea   国名：大韓民国  

開催年月日： 2019年5月

記述言語：英語   会議種別：口頭発表（一般）  

国名：大韓民国  

開催年月日： 2019年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：東京大学   国名：日本国  

開催年月日： 2018年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：ホテルウェルシーズン浜名湖   国名：日本国  

開催年月日： 2018年9月

記述言語：英語   会議種別：口頭発表（招待・特別）  

開催地：Tianjin, China   国名：中華人民共和国  

開催年月日： 2018年8月

記述言語：英語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2018年1月

記述言語：英語   会議種別：口頭発表（招待・特別）  

開催地：京都ガーデンパレスホテル(京都市上京区）   国名：日本国  

開催年月日： 2017年9月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：古屋大学東山キャンパス   国名：日本国  

開催年月日： 2016年11月

記述言語：英語   会議種別：口頭発表（招待・特別）  

開催地：タワーホール船堀（東京都江戸川区船堀4-1-1）   国名：日本国  

開催年月日： 2016年7月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Newcastle City Hall, New South Wales, Australia   国名：オーストラリア連邦  

開催年月日： 2016年3月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：分子科学研究所   国名：日本国  

開催年月日： 2015年10月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：慶應義塾大学 矢上キャンパス 創想館   国名：日本国  

自動車の燃費向上に伴って、排気ガスの平均温度が低下し、触媒の低温領域での活性向上が求められている。本講演では、Galvanic Deposition法による卑金属とのバイメタル化と担体の修飾により低温領域での触媒燃焼活性を向上させた例を紹介する。

開催年月日： 2015年6月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：日本大学生産工学部スプリングホール   国名：日本国  

開催年月日： 2015年6月

記述言語：英語   会議種別：口頭発表（招待・特別）  

開催地：愛媛大学南加記念ホール   国名：日本国  

開催年月日： 2015年5月

記述言語：英語   会議種別：口頭発表（基調）  

国名：大韓民国  

開催年月日： 2015年1月

記述言語：英語   会議種別：口頭発表（招待・特別）  

国名：インド  

開催年月日： 2014年12月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：名古屋大学ベンチャー・ビジネス・ラボラトリー   国名：日本国  

開催年月日： 2014年12月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：富山大学水素同位体科研究センター会議室   国名：日本国  

開催年月日： 2014年10月

記述言語：英語   会議種別：口頭発表（招待・特別）  

国名：日本国  

開催年月日： 2013年11月 - 2013年12月

記述言語：英語   会議種別：口頭発表（一般）  

開催地：Dhahran, Saudi Arabia   国名：日本国  

開催年月日： 2013年11月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：ホテル ルブラ王山(名古屋市)   国名：日本国  

開催年月日： 2013年11月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：静岡大学浜松キャンパス   国名：日本国  

開催年月日： 2013年1月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：名古屋大学   国名：日本国  

開催年月日： 2012年11月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：あいち産業科学技術総合センター 愛知県刈谷市   国名：日本国  

開催年月日： 2012年11月

記述言語：英語   会議種別：口頭発表（招待・特別）  

国名：日本国  

開催年月日： 2012年10月

記述言語：英語   会議種別：口頭発表（招待・特別）  

国名：オーストラリア連邦  

開催年月日： 2012年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：九州大学   国名：日本国  

開催年月日： 2012年9月

記述言語：英語   会議種別：ポスター発表  

国名：フランス共和国  

開催年月日： 2012年9月

記述言語：英語   会議種別：ポスター発表  

国名：フランス共和国  

開催年月日： 2012年7月

記述言語：英語   会議種別：ポスター発表  

国名：日本国  

開催年月日： 2012年7月

記述言語：英語   会議種別：ポスター発表  

国名：日本国  

開催年月日： 2012年5月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：名古屋大学   国名：日本国  

開催年月日： 2011年11月

記述言語：英語   会議種別：口頭発表（一般）  

国名：中華人民共和国  

開催年月日： 2011年11月

記述言語：日本語   会議種別：口頭発表（招待・特別）  

開催地：広島大学   国名：日本国  

開催年月日： 2011年10月

記述言語：英語   会議種別：口頭発表（招待・特別）  

国名：大韓民国  

開催年月日： 2011年5月

記述言語：英語   会議種別：口頭発表（一般）  

国名：大韓民国  

開催年月日： 2010年9月

記述言語：英語   会議種別：口頭発表（招待・特別）