Ni-Doped BiVO4 with V4+ Species and Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting

摘要

Bismuth vanadate is a promising photoanode material for photoelectrochemical (PEC) water splitting, but its activity and stability need to be further improved. In this work, we synthesized Ni-doped BiVO 4 abundant with V 4+ species and oxygen defects through an in situ electrodeposition method. The eff ective doping can decrease the particle size of BiVO 4 and lead to the formation of V 4+ species/oxygen defects. Accordingly, the doped and defective BiVO 4 showed high optical absorption and rapid charge transfer, and further showed much higher PEC activity than pure BiVO 4 . Specifi cally, 5-Ni-BiVO 4 exhibits the highest activity in PEC water splitting, with a photocurrent of 2.39 mA/cm 2 at 1.23 V versus RHE (the reversible hydrogen electrode), which is 2.5 times higher than pure BiVO 4 (0.94 mA/cm 2 ), and much higher incident photon-to-current effi ciency (IPCE) value of 45%(while only 25% for BiVO 4 at ca. 400 nm). This work provides an in situ method for the development of a high-performance photoanode.