A facile route for the preparation of ZnO/C composites with high photocatalytic activity and adsorption capacity

Abstract

This manuscript describes the deposition of carbon on the surface of ZnO nanoparticles via a simple adsorption and calcination process. The prepared ZnO/C sample was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and thermogravimetric analysis (TGA); the results indicated that carbon was successfully doped on the surface of the ZnO nanoparticles. The photocatalytic activity and adsorption capacity were evaluated by photocatalytic decomposition and adsorption of the dye methylene blue (MB) in aqueous solution. The results showed that the obtained ZnO/C sample exhibited much higher photocatalytic properties and adsorption capacity for MB than pure ZnO and carbon because of the formation of heteroarchitectures, which might have improved the separation of photogenerated electrons and holes. In particular, the pseudo-first-order rate constant of the ZnO/C sample was 0.326 min⁻¹, which was 10 times greater than that of pure ZnO. Moreover, the ZnO/C composites could remove dyes from different water sources like the Changjiang River water with high efficiency as well as from deionized water, greatly promoting their application in the area of environmental remediation.