Efficient interface-induced effect of novel reduced graphene oxide-CoS heteronanostructures in enhancing photocatalytic acitivities

•Reduced graphene oxide-CoS heterostructures were synthesized and studied.•The hybrids showed excellent sunlight-excited photocatalytic activities.•The hybrids had better activities than the CoS nanoparticles.•Initial pH and H2O2 remarkably affected the activities.•The enhanced charge transfer at the interface was confirmed by optical conductivity.

The interface-induced effects of heteronanostructures are attracting many attentions due to their potentials in photocatalysis applications. In this work, reduced graphene oxide-CoS (rGO-CoS) heteronanostructures were synthesized with a chemical method. The characterization of these nanomaterials was performed by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectra, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV-vis spectroscopy, and photocatalytic activities to understand the physical and chemical behavior of these materials. The effects of rGO/CoS ratio, initial solution pH, and H2O2 on the photodegradation of malachite green in a water were studied. The hybrids showed excellent sunlight-excited photocatalytic and Fenton-like photocatalytic activities to the dye, better than that of the CoS nanoparticles and enhanced as increasing rGO/CoS ratio and decreasing initial pH. The photodegradation rate constant, k obs, was determined under pseudo-first order conditions. The enhanced photoctalytic activities with rGO/CoS were ascribed to the enhanced charge transfer at the interface. The interface effect was confirmed by the calculations of band energy level and optical conductivity.

Graphical abstractDownload high-res image (154KB)Download full-size image