Two methods for microwave irradiation synthesis of TiO₂–ZnO–graphene ternary hybrids with enhanced photocatalytic activity

Abstract

In this study, graphene–zinc oxide–titanium dioxide (RGO–ZnO–TiO2) ternary hybrids are successfully synthesized by two methods called 'one step' and 'two steps', by using a simple microwave treatment of a solution containing graphene oxide, ZnO, TiO2, water and ethanol. Their morphology, structure, and photocatalytic performance in degradation of methylene blue, were characterized by scanning electron microscopy, energy dispersive x-ray analysis, x-ray diffraction analysis, Fourier transform infrared and UV–vis analysis. The results show that RGO–ZnO–TiO2 (GZT) hybrids (containing 7% graphene mass ratio) improve photodegradation efficiency 1.39- and 1.8-fold, compared with RGO–ZnO (GZT0) (containing 7% graphene mass ratio) and pure ZnO, because of reduction of electron–hole recombination in ZnO due to introduction of TiO2. Furthermore, we found that the photocatalytic activity in the 'one step' method is higher than in 'two steps'.