Substitution effects of In 3+ by Fe 3+ on photocatalytic and structural properties of Bi 2InNbO 7 photocatalysts

Abstract

The substitution effect of In 3+ by Fe 3+ on photocatalytic and structural properties of Bi 2InNbO 7 photocatalysts was investigated. The new photocatalysts, Bi 2MNbO 7 (M=Fe 3+, In 3+), were synthesized by the solid-state reaction and characterized by powder X-ray diffraction and Rietveld structure refinement. Bi 2MNbO 7 (M=Fe 3+, In 3+) crystallize in the same pyrochlore structure, but the lattice parameters decrease with In 3+ being substituted by Fe 3+. The formation rates of H 2 and O 2 evolutions from an aqueous methanol and a cerium sulfate solution, respectively, increase significantly with In 3+ being substituted by Fe 3+ under UV irradiation. The H 2 evolution was obtained from pure H 2O under UV irradiation with the Bi 2MNbO 7 (M=Fe 3+, In 3+) catalyst without co-catalyst such as Pt. The formation rate of H 2 evolution increases with In 3+ being substituted by Fe 3+. The Bi 2FeNbO 7 photocatalyst exhibits much higher photocatalytic activity than the well-known TiO 2 photocatalyst in pure water.