Surface modification and photocatalytic activity of distorted pyrochlore-type Bi2M(M=In, Ga and Fe)TaO7 photocatalysts

A series of novel Bi2MTaO7 (M=In, Ga and Fe) photocatalysts with a distorted pyrochlore-type structure have been developed by the solid-state reaction method. In order to search the optimum conditions used for evaluating the photocatalytic activities of these photocatalysts for H2 evolution, surface modification of the Bi2InTaO7 photocatalyst was conducted by loading different kinds and amounts of co-catalysts, respectively. The 0.2 wt%-Pt co-catalyst loaded was found to have the highest photocatalytic activity for H2 evolution from aqueous CH3OH/H2O solution under UV light irradiation. The photocatalytic activities of the Bi2MTaO7 (M=Ga and Fe) photocatalysts were also evaluated under the optimum conditions. Relevance between the photocatalytic activities of the series of novel Bi2MTaO7 (M=In, Ga and Fe) photocatalysts and their crystal structures, especially the lattice distortions and angles between the corner-linked MO6 (M=In, Ga, Fe and Ta) octahedral, are discussed.