The photo-catalytic effect of a copper modified (Ni, V, O) semiconductor complex catalyst on the direct synthesis of dimethyl carbonate (DMC) from CO, and CH3OH was investigated. The synthesized catalysts were fully characterized by temperature programmed reduction (TPR), X-ray diffraction (XRD). Ultraviolet visible drift reflection spectra (UV-vis DRS) and transmission electron microscopy (TEM). The nano-scale catalyst particles were observed with TEM and light absorbance was then predicted by UV-vis DRS spectra. The pressure and temperature dependencies of the photo-catalytic activity were studied. The results demonstrated that the catalytic activity was enhanced with the assistance of ultraviolet (UV) irradiation compared with the pure thermal and surface catalytic reaction under the same reaction conditions. (c) 2007 Elsevier B.V. All rights reserved.