Effect of Mn2+ incorporation on the photoelectrochemical properties of BiVO4

BiVO4 is a promising photoanode material for photoelectrochemical water splitting applications due to its narrow band gap, i.e., similar to 2.4 eV, suitable band-edge positions, non-toxicity, and high stability. Here, we report the synthesis of Mn2+-doped BiVO4 with varying concentrations of Mn2+ (0.2-1.0%) to improve the charge-transport properties of the catalyst. The addition of Mn enables forbidden d-d transitions, which are utilized to slow down the charge-carrier recombination and increase the efficiency. The highest efficiency was achieved in the case of the 1.0% Mn2+-BiVO4 photoanode, which exhibits a photocurrent density of 1.163 mA cm(-2) at 1.23 V and 1.56 mA cm(-2) at 1.4 V vs. RHE. The enhanced photoelectrochemical performance of Mn2+-BiVO4 implies a higher charge-carrier separation and an improved electrical conductivity. This suggests that Mn2+-doped BiVO4 may be used as a promising photoanode in future energy-conversion devices.