Nanonization of g-C3N4 with the assistance of activated carbon for improved visible light photocatalysis

Abstract

A visible light-driven g-C₃N₄/activated carbon composite photocatalyst (g-C₃N₄/AC) was prepared by a polymerization reaction of melamine and activated carbon. The photocatalytic activity of g-C₃N₄/AC was investigated by the degradation of phenol under visible light and sunlight irradiation. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) emission spectroscopy, Fourier transform infrared spectroscopy (FTIR), and N₂ adsorption–desorption isotherms were used for catalyst characterization. The results showed that g-C₃N₄/AC with 8 wt% AC had the best photocatalytic activity under visible light and sunlight irradiation. The mesoporous AC composite enables g-C₃N₄ to have a uniform particle distribution, less particle aggregation, and an increased specific surface area. A mechanism for the g-C₃N₄/AC photocatalyst was proposed, and the good efficiency for photodegradation was attributed to the increased surface area of the AC composite and decreased aggregation of g-C₃N₄, which facilitated the separation of photo-excited electron–hole pairs, and the strong adsorption capability of activated carbon, which accelerated the pollutant transfer rate and accumulation. Therefore, g-C₃N₄ can easily execute photocatalytic degradation in a pollutant-rich environment.