Composite Photocatalysts Containing BiVO4 for Degradation of Cationic Dyes

The creation of composite structures is a commonly employed approach towards enhanced

photocatalytic performance, with one of the key rationales for doing this being to separate

photoexcited charges, afording them longer lifetimes in which to react with adsorbed species. Here we

examine three composite photocatalysts using either WO3, TiO2 or CeO2 with BiVO4 for the degradation

of model dyes Methylene Blue and Rhodamine B. Each of these materials (WO3, TiO2 or CeO2) has a

diferent band edge energy ofset with respect to BiVO4, allowing for a systematic comparison of these

diferent arrangements. It is seen that while these ofsets can aford benefcial charge transfer (CT)

processes, they can also result in the deactivation of certain reactions. We also observed the importance

of localized dye concentrations, resulting from a strong afnity between it and the surface, in attaining

high overall photocatalytic performance, a factor not often acknowledged. It is hoped in the future

that these observations will assist in the judicious selection of semiconductors for use as composite

photocatalysts.