Facile synthesis and enhanced visible-light photoactivity of a g-C3N4/mullite composite

Abstract

A novel g-C₃N₄/mullite composite with enhanced visible light-driven photoactivity was prepared through a facile wetting chemical method. The microstructure, interfacial and optical properties of the obtained g-C₃N₄/mullite composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), surface area measurement (BET), and UV-visible diffused reflectance spectroscopy (UV-vis DRS), respectively. It is indicated that a tight interfacial combination was formed between g-C₃N₄ and mullite, which is beneficial for the transfer of electrons and the enhancement of quantum efficiency. Compared with pure g-C₃N₄ or a g-C₃N₄ + mullite physical mixture, the synthesized g-C₃N₄/mullite composites exhibit significantly enhanced photoactivity under visible light irradiation, almost 6.5 times that of the pure g-C₃N₄ and around 10.0 times that of a g-C₃N₄ + mullite physical mixture for the degradation of tetracycline. The enhanced photoactivity of the g-C₃N₄/mullite composite could be attributed not only to its stronger visible light adsorption and enhanced adsorption capacity for pollutants but also to the strong interfacial combination between g-C₃N₄ and mullite, effectively reducing the recombination probability of photogenerated electron–hole pairs.