Fluorine mediated photocatalytic activity of BiPO4

The fluorine doped BiPO4 (F-BiPO4) photocatalyst was synthesized via an in situ fluorination method. The lattice oxygen of BiPO4 was substituted by fluorine, resulting in the increased polarizability and thus an increased induced dipole moment of BiPO4, which can increase the separation efficiency of electron-hole pairs. The photocatalytic activity of BiPO4 was enhanced by about 30% when the molar ratio of F/Bi was 0.03. Not only the discoloration rate of methylene blue (MB) but also the mineralization rates of MB and phenol were accelerated by F-doping. The enhancement of photocatalytic activity by F-doping could be attributed to the stronger adsorption ability of the substrate, the larger amount of active facet and higher separation efficiency of electron-hole pairs resulted from the increased polarizability. Overdoping would decrease the photocatalytic activity due to the increased recombination rate of electron-hole pairs at high defect concentration. (C) 2013 Elsevier B.V. All rights reserved.