Photocatalytic water splitting with In-doped H2LaNb2O7 composite oxide semiconductors

The In-doped HLaNb2O7 oxide semiconductors synthesized by solid-state reaction followed by an ion-exchange reaction were found to be a novel composite photocatalyst system with enhanced activity for water splitting. Pt was incorporated in the interlayer of In-doped HLaNb2O7 by the stepwise intercalation reaction. The In-doped HLaNb2O7 powder samples were characterized with X-ray diffraction (XRD) and UV–vis diffuse reflectance spectrometry. The photocatalytic activities of Pt-loaded In-doped HLaNb2O7 and individual precursor materials were evaluated by H2 evolution from aqueous CH3OH solution under UV light irradiation. It was found that the composite In-doped HLaNb2O7 showed a higher H2 evolution rate in comparison with individual materials. The hydrogen production activity of In-doped HLaNb2O7 was greatly enhanced by Pt co-incorporation. The In content in the In-doped HLaNb2O7 system was discussed in relation to the photophysical and photocatalytic properties. As In content equal 5 mol%, the HLaNb2O7:In/Pt showed a photocatalytic activity of 354 cm3 g−1 hydrogen evolution in 10 vol% methanol solution under irradiation from a 100 W mercury lamp at 333 K for 3 h.