Coupling surface modification with cocatalyst deposition on BiVO4 photoanode to enhance charge transfer for efficient solar-driven water splitting

Bismuth vanadate (BiVO 4 ) has attracted wide attention as photoanode in water-splitting photoelectrochemical (PEC) devices. However, its catalytic performance is greatly limited by the serious charge recombination on the surface states. Herein, borate modified BiVO 4 plus additional CoPi cocatalyst (B-BVO/CoPi) is developed as photoanode for PEC cell via a simple soaking and electrodeposition process. Based on the electrochemistry tests and material characteristics, the borate groups [B(OH) 4 ] – is able to effectively prevent the charge recombination, while the outer CoPi cocatalyst enhance the activity toward oxygen evolution reaction . Therefore, the designed B-BVO/CoPi photoanode could obtain a high current density of 2.67 mA cm −2 at 1.23 V RHE with an onset potential of 0.29 V RHE , much higher than pristine BiVO 4 (0.78 mA cm −2 , 0.52 V RHE ). This work may provide a new insight for constructing multifunctional modified photoanodes for efficient solar conversion.