Synthesis of ZnO-decorated SnO2 nanopowder with enhanced photocatalytic performance

In recent years, heterogeneous photocatalysis has been paid much attention in the world as an important technique for treating wastewater. In this study, ZnO-decorated SnO2 nanopowders were prepared by hydrothermal method, and the effect of ZnO addition on the photocatalytic activity of SnO2 powder was investigated. The structure and morphology of the samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The composition was determined by X-ray photoelectron spectroscopy (XPS). The recombination behavior of photogenerated electrons and holes was studied by photoluminescence. The photocatalytic activity of the samples was tested by degradation of methylene blue (MB) which was used as a simulated organic pollutant. The experimental results show that compared with pure ZnO and SnO2 powders, the particle size of ZnO-SnO2 composites is reduced, photoluminescence is weakened, but the photocatalytic activity is improved. The enhancement in photocatalytic activity is attributed to the increased specific surface area due to the decrease of particle size and the formation of ZnO-SnO2 heterojunction which inhibits the recombination of photogenerated electrons and holes.