Deactivation of the TiO_2 Photocatalyst by Coupling with WO_3 and the Electrochemically Assisted High Photocatalytic Activity of WO_3

摘要

Patterned TiO_2 stripes were formed on a sol-gel crystalline WOa film by using a chemically modified sol-gel method (pat-TiO_2/WO_3),and the coupling effect on the photocatalytic activity was studied.Although the photoinduced electron transfer from TiO2 to WO_3 was confirmed by labeling and visualization of the reduction sites with Ag particles,the photocatalytic activities of TiO2 for both the gas-phase oxidation of CH_3CHO and the liquid-phase oxidation of 2-naphthol decreased significantly with the coupling.This finding was rationalized in terms of the decrease in the rate of the electron transfer from the semiconductor-(s) to O_2 with the coupling,which was estimated from the kinetic analysis of the photopotential relaxation.When the excited electrons were removed by a SnO_2 underlayer,the Wó_3 film exhibited a high photocatalytic activity exceeding that of TiO_2 for the oxidation of 2-naphthol.