Synergetic effects by Co2+ and PO43- on Mo-doped BiVO4 for an improved photoanodic H2O2 evolution

The efficiency of hydrogen peroxide evolution reaction (H2O2ER) by photoanodic water oxidation is normally limited by low yield and poor selectivity. In this work, the surfaces of Mo doped BiVO4 are modified by Co2+ and PO43- ions (CPMB), which has been used as the photoanode with improved H2O2 yield and selectivity. The optimal evolution rate of the CPMB is ca. 0.23 µmol·min−1·cm−2, corresponding to 2.5 times to the pristine BiVO4 photoanode, and the faradaic efficiency of CPMB photoanode for H2O2ER is ca. 26%. In this study, the mechanism for the improved H2O2 evolution performance of CPMB has been investigated, indicating that PO43- ions mainly promote the formation of the •OH by dissociation of H2O, while Co2+ ions accelerate the conversion of the •OH for the subsequent H2O2 evolution. This study offers the strategy for designing an efficient photoelectrochemical system with optimized solar conversion efficiency for H2O2 production.