A Zn-doped Lu2O3/Ga2O3 (Z-LGO) composite oxide semiconductor was synthesized by the solid-state reaction method. The Z-LGO powder samples were characterized with powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS). The results showed that the Z-LGO was mainly composed of the Zn-doped Lu2O3 and Ga2O3, of which the particle sizes were 0.5-3.0 mum and the average compositions were consistent with the raw materials used. The photophysical and photocatalytic properties of the Z-LGO powder samples were examined. It was found that the Z-LGO was a novel composite photocatalyst for stoichiometric water splitting under UV light irradiation. (C) 2003 Elsevier B.V. All rights reserved.