Synthesis, characterization and photocatalytic applications of various Fe2O3-ZnO-bentonite nanostructures

In this study, Bentonite/ZnO/Fe2O3 nanocomposite was prepared by decorating ZnO/Fe2O3 nanoparticles on the bentonite surface to improve the photocatalytic performance of ZnO/Fe2O3 nanocomposites under visible light irradiation. Prepared ZnO/Fe2O3 and Bentonite/ZnO/Fe2O3 nanocomposites were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope and energy dispersive X-ray (SEM-EDX) analysis. In order to determine optimal conditions in the photocatalysis process, the effect of parameters such as catalyst amount, initial dye concentration and time on the photodegradation of RhB was investigated. Optimal conditions were determined as 5 mgL-1 initial dye concentration and 50 mgL-1 catalyst amount under visible irradiation. Under these conditions, the photocatalytic degradation efficiencies of RhB over ZnO/Fe2O3 and Bentonite/ZnO/Fe2O3 nanocomposites were obtained as 79.4% and 100%, respectively, at 90 minutes. The degradation kinetics were found to be compatible with pseudo-first-order kinetics. In order to determine the contribution of reactive species responsible for the photocatalytic degradation of ZnO/Fe2O3 and Bentonite/ZnO/Fe2O3 nanocomposites, radical scavenging experiments were performed and a possible mechanism was proposed.