Photocatalysis over titania on iron oxide

Abstract
Photocatalytic activity of TiO₂ deposited on spherical sub micron-sized Fe₂O₃ particle was investigated under ultraviolet or visible light. The Fe₂O₃ particles were prepared using a spray pyrolysis of aqueous Fe(NO₃)₃ solution in air flow. TiO₂ was deposited on Fe₂O₃ particle by irradiation of ultraviolet or visible light to the suspension of Fe₂O₃ particle and a TiO₂ precursor. When TiO₂ was formed under visible light (TiO₂/Fe₂O₃-VIS), there were reasonable trends in the phase shift of PAS signal and EDX signal of Ti. However, there was no trend for the case of ultra violet irradiation (TiO₂/Fe₂O₃-UV). TiO₂/Fe₂O₃-VIS showed higher rates of decomposition of organic compound, of decrease in contact angle of water drop, and of decrease in the number of E. coli under visible light than TiO₂/Fe₂O₃-UV or TiO₂ film. From the results, it was suggested that TiO₂/Fe₂O₃-VIS had a regular thin layer of TiO₂ compared to TiO₂/Fe₂O₃-UV and the photo-generated carrier(s) in iron oxide migrated to the surface of TiO₂ in the case of TiO₂/Fe₂O₃-VIS.