Graphene oxide modified g-C3N4 hybrid with enhanced photocatalytic capability under visible light irradiation

Abstract

Graphene oxide modified g-C₃N₄ (GO/g-C₃N₄) with efficient photocatalytic capability under visible light irradiation was fabricated by sonochemical approach. Transmission electron microscopy images demonstrated that GO was two-dimensional sheets with chiffon-like ripples and the g-C₃N₄ possessed a layered structure. GO was overlaid on the surface of g-C₃N₄ in the GO/g-C₃N₄ hybrids. The UV–vis diffuse reflectance spectra showed that the GO/g-C₃N₄ hybrid had intense optical absorption in the visible light region. Photoluminescence spectra confirmed that the separation efficiency of photogenerated charge in GO/g-C₃N₄ was more intensive than pristine g-C₃N₄, indicating the GO acts as a separation centre and electron acceptor in the GO/g-C₃N₄ hybrid. The effective photogenerated charge separation efficiency lead to a remarkable improvement in the visible light photocatalysis. The pseudo-first-order kinetic constants of photocatalytic degradation of rhodamine B and 2, 4-dichlorophenol under visible light irradiation with GO/g-C₃N₄ were 3.80 and 2.08 times as large as that with pristine g-C₃N₄, respectively. This work indicates that the metal-free GO/g-C₃N₄ hybrid photocatalyst is a promising material in waste control, and GO could be an excellent material to combine with other semiconductors to make composites.