Ni-Doped BiVO₄ photoanode for efficient photoelectrochemical water splitting

BiVO₄ (BVO) based photoanode is one of the most mega-potential materials for solar water splitting while suffers from poor charge transfer and separation efficiency limit its practical application. Herein, FeOOH/Ni-BiVO₄ photoanode synthesized by the facile wet chemical method were investigated for improved charge transport and separation efficiency. The photoelectrochemical (PEC) measurements demonstrate that the water oxidation photocurrent density can reach as high as 3.02 mA cm⁻² at 1.23 V vs RHE, and the surface separation efficiency can be boosted to 73.3 %, which increases around 4 times comparing with that of pure sample. Further depth studies showed that the Ni doping can effectively promote hole transport/trapping and introduce more active sites for the oxidation of water, while FeOOH co-catalyst could passivate the Ni-BiVO₄ photoanode surface. This work provides a model for the design of BiVO₄-based photoanodes with combined thermodynamic and kinetic advantages.