Study on photocatalytic performance of coupled semiconductor supported metal materials

M/V2O5-TiO2(M=Pd, Cu, Ni and Ag) photo catalysts were prepared by sol-gel and impregnation-reduction methods. The surface structure, adsorption property, photo absorption performance and photo catalytic performance of M/V2O5-TiO2 catalysts were characterized by XRD, TPR, IR, TPD, UV-Vis DRS and photoreactor techniques. The results showed that the supported metallic M(M=Pd, Cu, Ag) on coupled semiconductor V2O5-TIO2 restrained the transformation from anatase TiO2 to rutile TiO2, Blue shifting of photo absorption edge and increasing of the photo absorption capacity to visible light Of V2O5-TiO2 semiconductor were observed clearly after the addition of metallic M(M=Pd, Cu, Ag). The photo absorption performance decreases in the order of Pd/V2O5-TiO2, Cu/V2O5-TiO2, Ag/V2O5-TiO2 and Ni/V2O5-TiO2. It can be concluded from analysis results that the adsorption property of the solid materials and adsorption states Of CO2 and C3H6 are the key to reaction. CO2 can not form the horizontal adsorption state on Ag/V2O5-TiO2, this results in no target products and low photo quantum efficiency. Pd/V2O5-TiO2 semiconductor with better photo absorption performance absorbs CO2 too strongly, thus increasing the desorption temperature of horizontal adsorption state and lowering its quantum efficiency. The Cu/V2O5-TiO2 with CO2 desorption temperature close to that of C,H, realizes "photo-surface-thermal" synergistic effects and improves photo quantum efficiency to 15.1%.