A5037755953- Catalytic Processes in Materials Science
- Advanced Chemical Physics Studies
- Nanomaterials for catalytic reactions
- Catalysis and Oxidation Reactions
- Surface and Thin Film Phenomena
- Nanocluster Synthesis and Applications
- Semiconductor materials and devices
- Diamond and Carbon-based Materials Research
- Boron and Carbon Nanomaterials Research
- Copper-based nanomaterials and applications
- ZnO doping and properties
- Graphene research and applications
- Gas Sensing Nanomaterials and Sensors
- Semiconductor materials and interfaces
- Physics of Superconductivity and Magnetism
- Catalysis and Hydrodesulfurization Studies
- Atmospheric and Environmental Gas Dynamics
- Organic and Molecular Conductors Research
- Metal-Catalyzed Oxygenation Mechanisms
- Photosynthetic Processes and Mechanisms
- Language, Metaphor, and Cognition
- Porphyrin and Phthalocyanine Chemistry
- Hydrocarbon exploration and reservoir analysis
- Coal Properties and Utilization
- Electron and X-Ray Spectroscopy Techniques
Research Organization for Information Science and Technology
2020-2023
Keio University
1989-2022
Kyoto University
2014-2021
Osaka University
2016-2021
Oita University
2019
Japan Organization for Metals and Energy Security (Japan)
2019
University of Tsukuba
2009-2017
Kyushu University
1986-2016
Kyushu Institute of Technology
2009-2016
Hokkaido University
2009-2010
Site-directed mutants of cytochrome P-450cam (the P-450 that acts as the terminal monooxygenase in d-camphor system), which threonine-252 had been changed to alanine, valine, or serine, were employed study role hydroxy amino acid reaction. The mutant enzymes expressed Escherichia coli and purified by a conventional method. All presence exhibited optical absorption spectra almost indistinguishable from those wild-type enzyme their ferric, ferrous, oxygenated, carbon monoxide ferrous forms. In...
Abstract When gold is deposited as nanoparticles (NPs) with mean diameters of 2–5 nm or clusters below 2 onto a variety supports such metal oxides, carbons, polymers, etc., the supported Au NPs exhibit unique catalytic properties, while bulk almost inert catalyst. A lot research works indicate that key factors catalysis by are selection supports, control NP size, shape NPs, and strong junction between because perimeter zone around acts active site for many reactions. In order to elucidate...
In spite of numerous efforts, the nature active oxygen generated at perimeter Au/TiO2 catalysts remains elusive; e.g., it is unclear whether species atomic or molecular oxygen. Using plane-wave density functional theory (DFT) and rutile (110)-supported Au rod models, we have examined various for their stability reactivity to CO. Our calculation finds that O2 attached endon a pentacoordinate Ti site (Ti5c) as well (Ti-OO-Au) transient state, turning into states with both O Ti5c. The latter...
Nanostructured LiMnO2 integrated with Li3PO4 was successfully synthesized by the mechanical milling route and examined as a new series of positive electrode materials for rechargeable lithium batteries. Although uniform mixing at atomic scale between not anticipated because noncompatibility crystal structures both phases, our study reveals that phosphorus ions excess dissolve into nanosize crystalline first evidenced elemental mapping using STEM-EELS combined total X-ray scattering,...
Abstract The aim of this study is to select an appropriate method for CH 4 adsorption in organic nanopores shale‐gas development. Molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations were performed. Three comparison studies included: (i) the behavior kerogen using different schemes dispersion correction, (ii) graphite MD GCMC simulations, (iii) simulations. result was reliable when a particle‐mesh Ewald scheme or cut‐off ≥1.5 nm without correction. simulation results...
The aggregation of Au atoms onto a dimer (Au₂) on MgO (001) surface was calculated by restricted (spin-un-polarized) and unrestricted (spin-polarized) density functional theory calculations with plane-wave basis the approximate spin projection (AP) method. included contamination errors 0.0⁻0.1 eV, were removed using AP potential energy curves for reaction estimated different owing to estimation open-shell structure calculations. These results show importance correction error calculation...
A 4.27-kilobase insert from a HindIII DNA library of Pseudomonas putida carrying the CAM plasmid allowed coordinate expression genes camD and camC under control camR, an upstream regulator. The gene specifies cytochrome P-450cam, 5-exo-alcohol dehydrogenase. 1.38-kilobase deletion results in constitutive camD; transformation trans restores substrate control, indicating that camR is negative
The effects of spin contamination errors on the activation barriers catalytic NO reduction by TiO2/Ag and ZrO2/Cu core-shell catalyst models were investigated using an approximate projection method unrestricted density functional theory calculation with plane-wave basis set. estimated barrier system increased (0.03 eV), whereas that decreased (0.04 eV) after correction error. This difference in two systems can be attributed to their surface structures. error obtained for was larger than gas...
Abstract Interactions between nanosized Au cluster models (Au rods, ribbons, and film) rutile TiO2 (110) modeled surfaces (stoichiometric: sTiO2, reduced: rTiO2, Cl-adsorbed: Cl-rTiO2) were determined using density functional theory. The Au–Au bonds are weakened the Au–Ti strengthened because oxygen defect sites in rTiO2 donate electrons to models. These interactions suppress aggregation of on surface. However, Cl atoms more strongly adsorbed at site than Au. amount transferred from Cl-rTiO2...
CO oxidation over a rutile TiO2(110) surface supporting tetrahedral Au10 cluster has been examined by plane-wave DFT calculations. O2 adsorbs sideon to the pentacoordinate Ti site of oxide support with large energy gain (∼ 2 eV), activated peroxide state. adsorption on is much weaker. The stability and activation state depends weakly distance cluster. On next cluster, reacts adsorbed yield CO2 very small barrier 0.13 eV. more remote site, gaseous 0.55 Thus, + reaction faster at perimeter...
Forecast experiment is made using a 13-level 42km-mesh primitive equation model for the extremely intense rainstorm event which occurred over western Japan on 23 July 1982. The was associated with meso-α-scale depression and low-level convergence line developed in subtropical frontal zone, but not an synoptic-scale trough. large amount of precipitation (maximum-500mm) concentrated narrow area (-100km square) short time span (6-12 hours).Several aspects including concentration rainfall,...
Titania-covered Ag catalysts were examined by density functional theory calculations for their potential toward NOx reduction. The modeled as an ultrathin rutile(110) layer covering a Ag(112) surface. NO was reduced CO through 2NO → N2O + O, N2 and O CO2. barriers calculated to be 0.5 eV or lower. key this striking reactivity electronic charge transfer from via TiO2.
Abstract Currently, there is a strong demand for new automotive catalysts with improved low‐temperature activity and reduced precious metal use. Such must undergo simultaneous CO/hydrocarbon oxidations NO reduction. A Pd catalyst supported on Mn‐modified hexagonal YbFeO 3 (Pd/Mn‐YFO) exhibited extremely high at low temperature via Mars‐van Krevelen (MvK) mechanism involving lattice oxygen vacancy site in the support. reduction proceeded by CO C H 6 oxidation of Pd/Mn‐YFO, catalytic 1.0 wt%...
The strong metal–support interaction (SMSI) prompts the reductive treatment-induced encapsulation of platinum group metal (PGM) nanoparticles by reducible oxide catalyst supports and therefore often leads to negative outcomes, such as a decrease in catalytic activity. Herein, SMSI effect was found benefit model reaction automotive exhaust gas purification, namely reduction NO with C3H6 CO over Pd/Ca2AlMnO5+δ. treatment Pd/Ca2AlMnO5+δ induced epitaxial growth (111) plane MnO–CaO solid...
The effect of TiO2 crystal structures (rutile, anatase, and brookite) on low-temperature CO oxidation catalyzed by Au/TiO2 was determined. catalytic activities with different are identical when the Au loadings mean diameters equal. Additionally, present work confirmed that active sites catalysts at perimeters supported nanoparticles. results will contribute to theoretical calculations for clarification mechanism Au/TiO2-catalyzed oxidation.
Abstract In this paper, we present an improved method to predict the methane adsorption isotherm for a real shale sample using molecular dynamics (MD) simulation with realistic kerogen model. We compare our results both experiment and on basis of simple graphite model, show how procedure leads creation more accurate isotherms at wide range pressure. A Marcellus was chosen as example demonstrate calculate MD simulations. Type II model selected dry gas window. The constructed bulk contains...
It is well known that unrestricted density functional theory (UDFT) calculations include spin contamination errors. While errors in UDFT/plane-wave have not been clarified thus far, some effects of these are investigated. Recently, our group estimated calculation results by developing and applying the approximate projection (AP) scheme [Chem. Phys. Lett., 701: 103 (2018), Mol. Phys., 117: 2251 (2019), Molecules, 24: 505 Appl. Express, 12: 115506 (2019)]. In this study, a systematic...