Photocatalytic degradation of azure B under visible light irradiation by reduced graphene oxide–NiS composite

A composite of reduced graphene oxide (RGO) and nickel sulfide (NiS) was prepared via mechanochemical method and further characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and energy dispersive analysis of X-rays (EDAX). NiS was prepared via precipitation method, and RGO was prepared via reduction of graphene oxide. The photocatalytic performances of as prepared RGO/NiS composite, RGO and NiS were evaluated using azure B model system. The composite exhibited good photocatalytic activity as compared to NiS as well as RGO. The optimum conditions obtained for the photocatalytic degradation of azure B were the following: pH = 8.0, [Azure B] = 2.0 × 10–5 M, amount of composite = 0.10 g, and light intensity = 50.0 mW·cm–2. The rate of degradation of azure B with the composite was found to be 1.79 × 10–4s–1.