Hiroaki Mametsuka

Photocatalytic oxygen evolution on α-Fe₂O₃ films was studied using the Fe³⁺ ion as a sacrificial oxidizing agent. The reaction conditions affecting the oxygen evolution rate, i.e. anion, Fe³⁺ concentration, pH, Fe³⁺/Fe²⁺ equilibrium concentration and dependence of irradiation wavelength, were investigated. The reaction rate increased with increase of both the Fe³⁺ ion concentration and the solution pH. Oxygen evolution ceased at an Fe³⁺ :Fe²⁺ ion concentration ratio of 3:7–4: 6. The reaction rate decreased rapidly for longer-wavelength irradiation (above around 400 nm), which is considerably shorter than the α-Fe₂O₃ bandgap of ca. 600 nm (2.1 eV).

The photocatalytic decomposition of liquid water on Pt-loaded TiO2 (Pt/TiO2) catalysts was investigated. The results obtained by XPS and XRD measurements o

A titanium-boron binary oxide has been prepared by the sol-gel method and used as a photocatalyst for the decomposition of water. The structure of titanium oxide species in the Ti/B binary oxide was amorphous before and crystal after calcination in O₂, while the boron oxide species retained its amorphous state. Pt-loaded Ti/B photocatalysts were found to decompose water stoichiometrically in aqueous suspension systems. Their photocatalytic activities decreased markedly with increase in the calcination temperature, indicating that the photocatalytic activity of the Ti/B binary oxide was strongly dependent on the crystal phase of the titanium oxide.