Search

Bismuth vanadate (BiVO 4 ) is a prospective candidate for photoelectrochemical (PEC) water oxidation, but its commercial application is limited due to the serious surface charge recombination. In this work, we propose a novel and effective electrochemical reduction strategy combined with co-catalyst modification to manipulate the surface states of the BiVO 4 photoanode. Specifically, an ultrathin amorphous structure is formed on the surface of BiVO 4 after electrochemical reduction ascribed to the breaking of the surface metal-O bonds. Photoelectrochemical measurements and first-principles calculation show that the electrochemical reduction treatment can effectively reduce the surface energy, thereby passivating the recombined surface states (r-ss) and increasing the mobility of photogenerated holes. In addition, the FeOOH co-catalyst layer further increases the intermediate surface states (i-ss) of BiVO 4 , stabilizes the surface structure and enhances its PEC performance. Benefiting from the superior charge transfer efficiency and the excellent water oxidation kinetics, the -0.8/BVO/Fe photoanode achieves 2.02 mA cm -2 photocurrent at 1.23 V RHE (2.4 times that of the original BiVO 4 ); meanwhile, the onset potential shifts 90 mV to the cathode. These results provide a new surface engineering tactic to modify the surface states of semiconductor photoanodes for high-efficiency PEC water oxidation.