Enhanced photodegradation ability of solvothermally synthesized metallic copper coated ZnO microrods

One-pot synthesis of metal-metal oxide composite as well as the effect of the interface reaction between the two components were few investigated. In this work, highly active photocatalysts, zinc oxide (ZnO) and metallic copper (Cu) coated ZnO microrods were facilely synthesized by one-pot solvothermal synthesis and a series of methods was employed to characterize their structure and composition. It was suggested that the ZnO microrods served as the core and were coated by metallic Cu. The obtained samples were used as photocatalyst and the results of the photocatalytic degradation of methylene blue suggested that under visible light irradiation, the Cu coated ZnO microrods were more efficient than the ZnO microrods and commercial titania (TiO2, P25). However, under UV light irradiation, the Cu coated ZnO microrods did not show much advantage for the degradation compared to the ZnO microrods. It was revealed that on the one hand, the surface defects as well as the electron transportation ability of the Cu on the ZnO microrods were responsible for the high activities upon their exposure to the visible light and on the other hand, under UV light, the presence of Cu might cause the faster recombination of electron-hole (e-/h(+)) pair of the ZnO microrods and led to different performances depended on the Cu amount. In conclusion, the proper amount of Cu coated ZnO demonstrated that it could be used as a potential photocatalyst, which can be operated both at visible and UV light irradiation. It is expected that the present strategy reported here could enrich the method for designing new metal-metal oxide hybrid photocatalysts.