Preparation and characterization of GO/Ag3PO4 composite photocatalyst and its visible light photocatalytic performance

Abstract

Graphene oxide (GO) was fabricated from graphite powder by Hummers oxidation method and then, under ultrasonic irradiation, a series of GO/Ag3PO4 composite photocatalysts (4% (w, mass fraction) GO/Ag3PO4, 8% GO/Ag3PO4, 16% GO/Ag3PO4, 32% GO/Ag3PO4) were synthesized by a facile liquid deposition process. The products were characterized by N2-physical adsorption, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectra, Fourier transform infrared (FT-IR) spectroscopg, and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The effect of GO content on the photocatalytic activity of Ag3PO4 was evaluated by photocatalytic degradation of methyl orange (MO) under visible light irradiation. The results show that GO can be easily dispersed into Ag3PO4, producing a well-connected GO/Ag3PO4 composite. Coupling of GO largely enhanced the surface area of the catalyst and the adsorption of MO. At the optimal GO content (16%), the degradation rate of MO over GO/Ag3PO4 was 83% after 120 min of light irradiation, exhibiting 7.5 times higher activity than that of pure Ag3PO4. The increase in photocatalytic activity and stability can be mainly attributed to the coupling of GO, which increased the surface area and suppressed the recombination rate of electron-hole (e-/h+) pairs and generated greater numbers of active free radicals.