A5077501800- Fuel Cells and Related Materials
- Electrocatalysts for Energy Conversion
- Conducting polymers and applications
- Magnetic and transport properties of perovskites and related materials
- Catalytic Processes in Materials Science
- Advanced Condensed Matter Physics
- Advancements in Solid Oxide Fuel Cells
- Electrochemical Analysis and Applications
- Multiferroics and related materials
- Electronic and Structural Properties of Oxides
- Catalysis and Oxidation Reactions
- Advanced battery technologies research
- Advancements in Battery Materials
- Ferroelectric and Piezoelectric Materials
- Advanced Battery Materials and Technologies
- Machine Learning in Materials Science
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Advanced Battery Technologies Research
- Rare-earth and actinide compounds
- Polymer Nanocomposites and Properties
- Catalysis and Hydrodesulfurization Studies
- Polymer crystallization and properties
- Catalysts for Methane Reforming
- Inorganic Chemistry and Materials
Photonics Electronics Technology Research Association
2024-2025
Yamanashi Research Institute
2024
Cubic (United States)
2023
Nissan (Japan)
2011-2022
Nissan (United Kingdom)
2011-2020
Naval Hospital Yokosuka Japan
2017
Yokohama National University
2012
Waseda University
1997-2006
Kyushu Tokai University
2004
Abstract Solid silicon monoxide is an amorphous material which has been commercialized for many functional applications. However, the structure of a long-standing question because uncommon valence state in oxide. It deduced that undergoes unusual disproportionation by forming silicon- and silicon-dioxide-like regions. Nevertheless, direct experimental observation still missing. Here we report characterized angstrom-beam electron diffraction, supplemented synchrotron X-ray scattering computer...
We have designed a chemically ordered face-centred tetragonal intermetallic PtFeCo (trimetallic) (fct-TM) alloy catalyst using simple solid-state impregnation method for the oxygen–reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs). The fct-TM has demonstrated both enhanced activity and durability, unlike many Pt alloys. chemical ordering of was verified by high-angle annular dark-field scanning transmission electron microscopy. ORR examined rotating-disk electrode...
We develop platinum–iron–nickel (PtFeNi) trimetallic alloy catalysts having a chemically ordered L10-type superlattice structure. The PtFeNi catalyst annealed at 800 °C possesses structure and exhibits oxygen reduction reaction (ORR) activity that is much higher than of the disordered commercial Pt supported on carbon black. Moreover, ORR specific activities in systems are enhanced more those PtFe PtNi bimetallic systems. Analyses situ X-ray absorption spectroscopy reveals Pt–Pt bond...
To develop zirconium oxide-based electrocatalysts for the oxygen reduction reaction (ORR), we attempted to clarify factors that affect ORR activity of cathodes. We prepared from oxy-zirconium phthalocyanine with multiwalled carbon nanotubes as electroconductive supports via heat treatment under a low partial pressure. evaluated density active sites, i.e., vacancies, using X-ray photoelectron spectroscopy (XPS), average particle size oxide particles transmission electron microscopy (TEM), and...
Abstract In the process of developing carbon-supported metal catalysts, determining catalyst particle-size distribution is an essential step, because this parameter directly related to catalytic activities. The most effectively determined by small-angle X-ray scattering (SAXS). When catalysts are supported high-performance mesoporous carbon materials, however, their mesopores may lead erroneous estimation if sizes and comparable. Here we propose a novel approach determination introducing...
In polymer electrolyte membrane fuel cells, carbon-supported platinum (Pt/C) catalyst particles require sufficient water condensation within the nanoscale pores to effectively utilize interior Pt catalysts. Since experimental visualizations with precision of this phenomenon are not yet possible, we utilized a Pt/C particle reconstructed from segmented nanoimaging powder, which served as computational domain for lattice density functional theory (LDFT) simulation condensation. Paired uptake...
The development of non-platinum electrocatalysts for oxygen reduction reactions (ORR) is required the commercialization polymer electrolyte fuel cells. We focused on highly stable group 4 and 5 metal oxide-based compounds in acidic media. In this study, we proposed precious-metal- carbon-free cathodes based oxides demonstrated superior durability by preparing titanium-niobium mixed with Ti4O7 (TixNbyOz + Ti4O7). ORR activity TixNbyOz higher than that Ti4O7, indicating might have active sites...
The influence of specific adsorption the sulfo group in perfluorosulfonic acid ionomer, Nafion, on oxygen reduction reaction (ORR) a carbon-supported Pt/C catalyst using thin-film rotating disk electrode was investigated. relationship between activity and coating with Nafion quantitatively evaluated through electrochemical measurements, operando X-ray absorption spectroscopy (XAS), CO stripping voltammetry. Activity decreased increasing ionomer-to-carbon weight ratios. To date, effect has...
Nagata et al. recently developed high-impact polyketone/polyamide-6 (PK/PA) alloys and investigated their mechanical properties (Nagata Polym. Prep. Jpn. 2006, 55, 4286−4287). This paper presents the results of investigations morphology, such as domain size PA PK, features crystalline phase PK (the long period thickness lamellae are deduced), change in form PK/PA alloys, using solid-state nuclear magnetic resonance (NMR), small-angle X-ray scattering (SAXS), transmission electron microscopy...
Nb2O5–WOx synthesized by a hydrothermal method having long nano-crystalline structure with ca. 10 nm diameter exhibited high catalytic activity in the Friedel–Crafts alkylations and acylations when it was calcined N2.
Zirconium oxide-based electrocatalysts with multi-walled carbon nanotubes as electroconductive support (ZrCxNyOz/MWCNT) were prepared by oxidation of oxy-zirconium phthalocyanine under low oxygen partial pressure and examined new non-platinum cathodes for polymer electrolyte fuel cells. The effect reheating treatment ZrCxNyOz/MWCNT in the temperature range from 900 to 1200°C 1 h nitrogen atmosphere on activity stability oxygen-reduction reaction (ORR) was investigated. at 1000°C enhanced ORR...
Understanding the degradation mechanism of Fe/N/C cathode catalysts in proton exchange membrane fuel cells (PEMFCs) is important. We studied an catalyst prepared from polyimide nanoparticles situ cell by X-ray absorption spectroscopy (XAS). This technique enables real-time monitoring Fe species during a operation. The K-edge spectra were recorded continuous operation cell. Initially operation, atomically isolated and their valence state was found to be 3+. gradually changed first few hours...
Carbon-free connected Pt–Fe nanoparticle catalysts exhibit excellent oxygen reduction reaction (ORR) activity. Unlike conventional ORR catalysts, comprise a beaded network structure formed by the connection of nanoparticles. The refined structural analyses reveal that comprises polycrystalline structure, whereas commercial Pt on carbon is single crystal. In addition, Pt-rich thin layer made three-to-four platinum atomic layers with high-index stepped facets was observed catalyst surface in...
<italic>In situ</italic> X-ray absorption spectroscopy has afforded a detailed structural and electronic characterization of newly developed stabilized Pt-skin/PtCo alloy nanoparticle catalyst for CO-tolerant H<sub>2</sub> oxidation.
This study elucidates the factors reducing CO2 methanation reaction temperature of TiO2-supported Ru catalysts prepared via polygonal barrel-sputtering method (Ru/TiO2(BS)) to investigate structure-sensitivity mechanism. The smaller nanoparticles deposited in Ru/TiO2(BS) (<4 nm) were amorphous RuO2 because air exposure after preparation, and their surfaces changed island-shaped structures consisting metal by H2 exposure. In this case, dissociative hydrogen was also adsorbed abundance on...
Abstract Electrochemical pre-doping of a silicon electrode was investigated to create new class rechargeable battery with higher energy density. The electrochemical reaction during formed high-quality solid electrolyte interface (SEI) on the surface particles, which improved charge and discharge cycle life small irreversible capacity. composition pre-doped particles characterized using transmission electron microscopy (TEM), state magic-angle-spinning (MAS) nuclear magnetic resonance (NMR)...
Abstract We report the results of high‐resolution transmission electron‐micrograph (TEM) observation, electron diffraction, and neutron diffraction (ND) measurements, which are sensitive to oxygen‐vacancies, for Ta‐oxide‐based oxygen‐reduction electrocatalysts used polymer electrolyte fuel cells (PEFCs). Both TEM ND indicate that highly active tantalum oxide (Ta 2 O 5 ) phase have an incommensurate long‐period structure with oxygen vacancies in oxides, forming three‐dimensionally ordered...
In order to make the PEFC gain in popularity, we are working on preparing non-precious metal catalysts for cathode oxygen reduction reaction (ORR). Our researches focus oxide-based compounds of group 4 and 5 metals. We have reported that compounds, particular, partially oxidized carbonitrides Zr1 Nb2, Ta3 had high stability catalytic activity ORR acidic solution. But it is hard prepare fine particle improve by using compounds. So tried different starting material.