Solar light irradiated photocatalytic activity of ZnO–NiO/rGO nanocatalyst

Abstract

The current study is based on the synthesis and characterization of ZnO–NiO/rGO nanohybrid for photocatalytic degradation of organic pollutants. The physicochemical properties of synthesized products were estimated by X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), field emission-scanning electron microscopy (FESEM), and Ultraviolet–Visible spectroscopy. The diffraction data showed the formation of binary metal oxide nanocomposite, containing ZnO in hexagonal whereas NiO in the cubic crystalline phase. XRD results revealed that the calculated crystallite size of NiO and ZnO in the ZnO–NiO nanocomposite was <20 nm. The spectroscopic results were found to be in close agreement with XRD data. The morphological analysis exposed the nano-island morphology of the product. The solar light assisted photocatalytic degradation outcome showed 89% degradation of methylene blue and 51% degradation of benzimidazole under similar conditions using ZnO–NiO/rGO nanohybrid. Moreover, the experiment showed that hydroxyl radicals, electrons, and holes were the main active species during the degradation mechanism. In contrast to the ZnO–NiO nanocomposite, the ZnO–NiO/rGO nanohybrid exhibited greater degradation efficiency. This superb photocatalytic performance of ZnO–NiO/rGO nanohybrid proved to be a durable candidate in the field of catalysis.