Enhancement of photocurrents due to the oxidation of water and organic compounds at BiZn2VO6 particulate thin film electrodes by treatment with a TiCl4 solution

Photocurrents due to water oxidation at BiZn2VO6 (Eg 2.4 eV) particulate thin film electrodes were largely enhanced by pre-treatment with an aqueous TiCl4 solution. Photocurrents for BiZn2VO6 electrodes with no TiCl4 treatment were also enhanced by the addition of organic compounds such as methanol and trimethyl amine to the aqueous electrolyte. Interestingly, such enhanced photocurrents by organic compounds were further enhanced by the TiCl4 pre-treatment. EDAX and SEM investigations showed the formation of a flock-like TiO2 overlayer on BiZn2VO6 particles after the TiCl4 treatment. The photocurrent enhancement by the TiCl4 pre-treatment is thus mainly attributed to the necking effect of the flock-like TiO2 overlayer, which facilitates the transport of photogenerated electrons within the BiZn2VO6 particulate thin film electrode.