Photocatalytic decomposition of water on mixed metal oxides with sunlight

Abstract

The photocatalytic decomposition of water into hydrogen and oxygen on various mixed metal oxides having tunnel or layered structures under sunlight and low-pressure mercury lamp has been studied. Modification of catalysts by proton-exchange, doping and loading metals and metal oxides was performed. The activity was enhanced by loading Pt and RuO2 for TiO2 and various mixed metal oxides, while a decrease in the activity was resulted from substitution of even a small amount of metal oxides. The role of Na2CO3 addition was depended upon the Pt-loading methods, indicating that the promotion effect was appeared only when Pt was loaded by in situ photochemical deposition. A novel wet-bed method which is extremely simple and effective for the production of hydrogen from the photocatalytic decomposition of water on powdered semiconductor oxides with sunlight has been also developed.