Visible light photocatalytic activity enhancement and mechanism of AgBr/Ag3PO4 hybrids for degradation of methyl orange

Novel AgBr/Ag3PO4 hybrids were synthesized via an in situ anion-exchange method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS) and UV-vis diffuse reflectance spectroscopy (DRS). Under visible light (lambda > 420 nm), AgBr/Ag3PO4 degraded methyl orange (MO) efficiently and displayed much higher photocatalytic activity than that of pure AgBr or Ag3PO4. X-ray photoelectron spectroscopy (XPS) suggests that AgBr/Ag3PO4 transformed to be Ag@AgBr/Ag3PO4@Ag system while remained good photocatalytic activity after 5 times of cycle experiments. In addition, the quenching effects of different scavengers proved that reactive center dot H and h(+) played the major role for the MO degradation. The photocatalytic activity enhancement of AgBr/Ag3PO4 is closely related to the efficient separation of electron-hole pairs derived from the matching band potentials between AgBr and Ag3PO4, as well as the good electron trapping role of Ag nanoparticles in situ formed on the surfaces of AgBr and Ag3PO4 particles during the photocatalytic reaction. (C) 2012 Elsevier B.V. All rights reserved.