The In-doped HLaNb(2)O(7) 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 HLaNb(2)O(7) by the stepwise intercalation reaction. The In-doped HLaNb(2)O(7) powder samples were characterized with X-ray diffraction (XRD) and UV-vis diffuse reflectance spectrometry. The photocatalytic activities of Pt-loaded In-doped HLaNb(2)O(7) and individual precursor materials were evaluated by H(2) evolution from aqueous CH(3)OH solution under UV light irradiation. It was found that the composite In-doped HLaNb(2)O(7) showed a higher H(2) evolution rate in comparison with individual materials. The hydrogen production activity of In-doped HLaNb(2)O(7) was greatly enhanced by Pt co-incorporation. The In content in the In-doped HLaNb(2)O(7) system was discussed in relation to the photophysical and photocatalytic properties. As In content equal 5 mol%, the HLaNb(2)O(7):In/Pt showed a photocatalytic activity of 354 cm(3)g(-1) hydrogen evolution in 10 vol% methanol solution under irradiation from a 100 W mercury lamp at 333 K for 3 h. (C) 2009 Elsevier B.V. All rights reserved.