Kyoto University · Materials Science
Professor Takaya Ogawa's research lab focuses on advancing sustainable energy technologies through the fundamental understanding and design of functional materials for energy conversion and storage. Key research directions include proton conduction mechanisms in hybrid and inorganic electrolytes, with an emphasis on developing materials for efficient fuel cells and water electrolyzers under low-humidity conditions. The lab combines computational materials science, advanced spectroscopy, and theoretical calculations to explore novel ion transport mechanisms—such as the packed-acid mechanism—and to design high-performance catalysts for ammonia synthesis and hydrogen production. Their work bridges materials chemistry, electrochemistry, and computational modeling to address critical challenges in clean energy applications.
Figures are computed from collected data and may differ slightly.
Available methods to analyze proton conduction mechanisms cannot distinguish between two proton-conduction processes derived from the Grotthuss mechanism. The two mechanistic variations involve structural diffusion, for which water movement is indispensable, and the recently proposed "packed-acid mechanism," which involves the conduction of protons without the movement of water and is typically observed in materials consisting of highly concentrated (packed) acids. The latter mechanism could imp
Water electrolysis for hydrogen production has received increasing attention, especially for accumulating renewable energy. Here, we comprehensively reviewed all water electrolysis research areas through computational analysis, using a citation network to objectively detect emerging technologies and provide interdisciplinary data for forecasting trends. The results show that all research areas increase their publication counts per year, and the following two areas are particularly increasing in
Ruthenium is the most effective catalyst reported to date for ammonia synthesis under mild conditions, especially when an electron promoter is used. However, electron donation from the promoter has not been sufficient because the promoter contacts with Ru only through its surface. Here, we report a Laves phase intermetallic bulk catalyst, YRu2, which has higher electron density on Ru. This is derived from large electron transfer from Y to Ru, which is first confirmed by X-ray absorption fine str
Fuel cells have been attracting significant attention recently as highly efficient and eco-friendly energy generators. Here, we have comprehensively reviewed all types of fuel cells using computational analysis based on a citation network that detects emerging technologies objectively and provides interdisciplinary data to compare trends. This comparison shows that the technologies of solid oxide fuel cells (SOFCs) and electrolytes in polymer electrolyte fuel cells (PEFCs) are at the mature stag
To examine the origin of the high proton conductivity of hybrid electrolytes, composites of an inorganic grain and an organic electrolyte polymer, the reaction mechanism for proton transfer at the surface of water-adsorbed zirconium phosphate, α-Zr(HPO4)2·H2O (ZrP), has been theoretically investigated as a first step in our research. Reaction paths and activation energies, which determine the proton conductivity, are examined by quantum chemistry calculations. In particular, the effects of adsor
Proton conduction in zirconium sulphate (ZrSO4) composed of a Lewis acid-base pair was studied. ZrSO4 exhibits non-humidified proton conductivity, comparable to other proton conductors under similar conditions. Ab initio calculation shows that a proton transfers in ZrSO4 from a Lewis acid to a Lewis base without a proton carrier.
Abstract The mechanism of proton transfer on the surface of zirconium phosphate monohydrate, α-Zr(HPO4)2·H2O (ZrP), has been first investigated by quantum chemistry calculation. The reaction paths and the activation energies along the paths are examined, and the effects of ZrP surface and phosphate groups on the proton conductivity are discussed.
In this study, as a proton-conducting material for polymer electrolyte fuel cell applications, the properties of an organic–inorganic electrolyte comprising zirconium sulfophenylphosphonate (ZrSPP) and sulfonated poly(arylene ether sulfone) (SPES) are investigated by changing the ZrSPP/SPES ratio. An increase in this ratio enhances proton conductivity and shifts the O–S–O wavenumber to a high value. As a proton-conducting material for polymer electrolyte fuel cell applications, the properties of
Proton conducting materials suffer from low proton conductivity under low-relative humidity (RH) conditions. Previously, it was reported that acid-acid interactions, where acids interact with each other at close distances, can facilitate proton conduction without water movement and are promising for overcoming this drawback [T. Ogawa, H. Ohashi, T. Tamaki and T. Yamaguchi, <i>Chem. Phys. Lett.</i>, 2019, <b>731</b>, 136627]. However, acid groups have not been compared to find a suitable acid gro
The qualitative and quantitative analytical methods were proposed for the simple and rapid determination of triacetin (TAc) in commercial gummy candies and other foodstuffs by gas chromatography (GC), thin layer chromatography (TLC) and infrared spectroscopy (IR). Each extract from the samples was obtained by pretreatment of the foodstuffs as follows: (A) Gummy candy was dissolved in warm water and the solution was extracted with chloroform. The organic (chloroform) layer was separated. (B) Samp
TiO2 thin films are promising as photocatalysts to decompose organic compounds. In this study, TiO2 thin films were deposited by reactive radio-frequency (RF) magnetron sputtering under various flow rates of oxygen and argon gas. The results show that the photocatalytic activity decreases as the oxygen-gas ratio is increased to 30% or less, while the activity increases under oxygen-rich conditions. It was observed that the crystal structure changed from anatase to a composite of anatase and ruti
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