Preparation of BiPO4/graphene photoelectrode and its photoelectrocatalyitic performance

In this work, a two-step electrodeposition method was employed to prepare BiPO4 nanorod/reduced graphene oxide/FTO composite electrodes (BiPO4/rGO/FTO). The BiPO4/rGO/FTO composite electrode showed the higher photoelectrocatalytic (PEC) activity for the removal of methyl orange than pure BiPO4, which was 2.8 times higher than that of BiPO4/FTO electrode. The effects of working voltage and BiPO4 deposition time on the degradation efficiency of methyl orange were investigated. The optimum BiPO4 deposition time was 45 min and the optimum working voltage was 1.2 V. The trapping experiments showed that hydroxyl radicals (•OH) and superoxide radicals (•O2) were the major reactive species in PEC degradation process. The BiPO4/rGO/FTO composite electrode showed the high stability and its methyl orange removal efficiency remained unchanged after four testing cycles. The reasons for the enhanced PEC efficiency of the BiPO4/rGO/FTO composite electrode was ascribed to the broad visible-light absorption range, the rapid transmission of photogenerated charges, and the mixed BiPO4 phase by the introduction of rGO in the composite electrode films.