[20p-C212-1~7] Hydrogen in oxides and its role

[20p-C212-2] Quantification of hydrogen and electronic-structure analysis of titanium oxides surfaces

〇Katsuyuki Fukutani^1,2 (1.IIS, Univ. Tokyo, 2.ASRC, JAEA)

Keywords:Hydrogen, Nuclear reaction analysis, Electronic structure

Metal oxides find various applications including a hydrogen sensor and photocatalytic water splitting, where the electronic structure of hydrogen and the effects of hydrogen on the substrate electronic structure are of crucial importance. Adsorption and absorption of hydrogen on TiO₂ and SrTiO₃ surfaces are investigated with nuclear reaction analysis (NRA) and photoemission spectroscopy (PES). When the surfaces are exposed to atomic hydrogen or low-energy hydrogen ions, adsorption and penetration of hydrogen on and into the surfaces are clearly recognized by NRA. Concomitantly, PES reveals significant band bending and presence of in-gap states suggesting electron transfer from hydrogen to the substrates.