CuS-ZnS decorated graphene nanocomposites: Synthesis and photocatalytic properties

Fabrication of porous nanocomposites was synthesized by incorporating CuS-ZnS nanospheres and graphene layers via a simple method for efficient photocatalytic performance. The transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) images showed that the as-prepared copper sulphide (CuS) and zinc sulphide (ZnS) nanomaterials are spherical in shape and uniformly dispersed in graphene layers. The strong bonding interaction between as-synthesized nanospheres and graphene layers were analysed by using XRD and XPS analysis. The Raman spectra analysis indicates the shifting of charge carriers between the nanospheres and graphene layers. The insertion of CuS-ZnS nanospheres significantly enhances the surface area, porosity, adsorbability and interplanar distances of the graphene layers due to the better synergistic effect. The formation of a p-n junction on the graphene surfaces was confirmed by Nyquist plot analysis. The photocatalytic degradation of methyl orange (MO) - rhodamine B (RhB) dyes mixture in aqueous solution of as-synthesized nanocomposites was compared with pristine graphene. The nanocomposites show better photocatalytic performance over a wide pH range of 4.45-10.38. The mechanism of photocatalytic degradation was also discussed. The stability and reusability of as-synthesized nanocomposites were also estimated. The obtained results showed the excellent dyes degradation efficiency of as-synthesized nanocomposites due to its excellent surface area, porosity, better UV light harvesting capacity and ultra-fast electron-hole transfer capacity. Hence, CuS-ZnS decorated Graphene is a potential photocatalyst for MO - RhB dyes mixture degradation in industrial applications.