The effects of ZnO morphology on photocatalytic efficiency of ZnO/RGO nanocomposites

Abstract

ZnO/RGO nanocomposites with different morphologies, including RGO/ZnO nanoparticles, RGO/ZnO nanosheets, RGO/ZnO nanospheres and RGO/ZnO nanorods were prepared through hydrothermal process, characterized by XRD, TEM, SEM, UV–vis spectra, electrochemical analysis, and tested in photocatalytic hydrogen production. It was found that the ZnO morphologies have great influence on photo absorption, separation efficiency of photo-generated charges and photocatalytic performance of ZnO/RGO nanocomposites. RGO/ZnO nanorods with a sandwich-like 3D structure, consisting of ZnO nanorods grown vertically on both sides of graphene sheets exhibited a highest photocatalytic H 2 production rate of 610, which is about 1.1 times, 1.9 times and 2.6 times more active than ZnO/RGO particles, ZnO/RGO nanospheres and ZnO/RGO nanosheets, respectively. The results of PL, CV curves and photocurrent measurements show that the superior photocatalytic performances of RGO/ZnO nanorods and RGO/ZnO nanoparticles originate from the higher transfer rate of photo-generated electron from ZnO to RGO , and repressed recombination of the photoinduced hole–electron pairs of ZnO, which is closely related with the morphology of ZnO and the strength of chemical interaction between ZnO and RGO .