Size effect induced activity enhancement and anti-photocorrosion of reduced graphene oxide/ZnO composites for degradation of organic dyes and reduction of Cr(VI) in water

RGO/ZnO composites with different size of ZnO particles have been fabricated via a one-step facile solvothermal method. The photocatalytic activities of these composites have been investigated toward dye degradation and Cr (IV) reduction in an aqueous phase. It is found that ZnO-S1, with relatively small particles size distribution, is able to hybridize with RGO sheet more efficiently than that for the hybridization of ZnO-S2, with large particles size distribution, with RGO sheet. Such a particle size effect leads the more efficient interfacial interaction between ZnO-S1 and RGO, which leads to both the enhanced photoactivity and the significantly decreased photocorrosion. In addition, we have also used the radicals scavengers technique to study the role of photoactive species involved in the photocatalytic degradation of dye and reduction of Cr (VI).