Synthesis of mesoporous SiO2/Cu2O–graphene nanocomposites and their highly efficient photocatalytic performance for dye pollutants

A mesoporous SiO2/Cu2O–graphene composite, a novel material, was successfully synthesized using a self-assembly method with tetraethyl orthosilicate (TEOS). During the reaction, Cu2O and silica nanoparticles were loaded on the graphene sheets. The mesoporous structure, morphology, pore diameter, pore volume, and surface area of the mesoporous SiO2/Cu2O–graphene composite photocatalysts were obtained via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), FT-IR spectra, nitrogen adsorption/desorption isotherms using the BET and BJH method and photocurrent analyses. The photocatalytic degradation of rhodamine B (RhB), methylene blue trihydrate (MB), and reactive black B (RBB) in an aqueous solution under visible light irradiation was observed via UV spectrophotometry after measuring the decrease in their concentrations. The mesoporous structure of silica nanoparticles with a large surface plays a major role in the increased photodegradation as well as in the decomposition by the catalysts. Through recycling experiments, we conclude that the mesoporous SiO2/Cu2O–graphene composite had good stability during photocatalysis under visible light irradiation. The mesoporous SiO2/Cu2O–graphene nanocomposite is expected to become a candidate material for photodegradation with excellent performance.