Substitution effects of In3+ by Fe3+ on photocatalytic and structural properties of Bi2InNbO7 photocatalysts

The substitution effect of In3+ by Fe3+ on photocatalytic and structural properties of Bi2InNbO7 photocatalysts was investigated. The new photocatalysts, Bi2MNbO7 (M = Fe3+,In3+), were synthesized by the solid-state reaction and characterized by powder X-ray diffraction and Rietveld structure refinement. Bi2MNbO7 (M = Fe3+, In3+) crystallize in the same pyrochlore structure, but the lattice parameters decrease with In3+ being substituted by Fe3+. The formation rates of H-2 and O-2 evolutions from an aqueous methanol and a cerium sulfate solution, respectively, increase significantly with In3+ being substituted by Fe3+ under UV irradiation. The H-2 evolution was obtained from pure H2O under UV irradiation with the Bi2MNbO7 (M = Fe3+, In3+) catalyst without co-catalyst such as Pt. The formation rate of H-2 evolution increases with In3+ being substituted by Fe3+. The Bi2FeNbO7 photocatalyst exhibits much higher photocatalytic activity than the well-known TiO2 photocatalyst in pure water. (C) 2001 Published by Elsevier Science B.V.