Synthesis of silver phosphate/graphene oxide composite and its enhanced visible light photocatalytic mechanism and degradation pathways of tetrabromobisphenol A.

In the present study, silver phosphate/graphene oxide (Ag3PO4/GO) composite was synthesized by ultrasound-precipitation processes. Afterwards, physicochemical properties of the resulting samples were studied through scanning electron microscope, transmission electron microscope, X-ray diffraction, N2 adsorption/desorption, UV-vis diffuse reflectance spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, surface photovoltage spectroscopy and photoelectrochemical measurements. Results indicated that spherical Ag3PO4 displayed an average diameter of 150 nm and body-centered cubic crystal phase, which was integrated with GO. In addition, the visible light absorbance, charge separation efficiency and lifetime of Ag3PO4 were significantly improved by integration with GO. In addition, Ag3PO4/GO composite was applied to decompose tetrabromosphenol A (TBBPA) in water body. It was found that TBBPA could be completely decomposed within 60 min illumination. Furthermore, several scavenger experiments were conducted to distinguish the contribution of reactive species to the photoctalytic efficiency. Moreover, the enhanced visible light mechanism of Ag3PO4/GO was proposed and discussed. Eventually, several PC decomposition pathways of TBBPA were identified including directly debromination and oxidation, and subsequently further oxidation and hydroxylation processes.