Synthesis and characterization of reduced graphene oxide/cobalt sulfide heterostructures as the visible-light-driven photocatalysts

This work reports the synthesis of cobalt sulfide and reduced graphene oxide-cobalt sulfide composites (rGO@CoS) via a facile hydrothermal method for wastewater remediation. The SEM image of CoS unveils its
characteristic sandwiched structure and hexagonal shape. The structural, electronic, and optical properties of the prepared samples were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, and UV–visible diffuse reflectance spectroscopy, respectively. A high degree of sp2 carbon occurred in rGO@CoS. To study the photocatalytic activity, degradation of methylene blue was performed in an aqueous solution under visible light irradiation. The results indicate that rGO could promote the photocatalytic activity of CoS through a synergistic effect and suppress e􀀀 /h+ pairs recombination by shortening the charge transportation time. The addition of rGO also enhanced the adsorption ability of methylene blue.