Electronegative Cl− modified BiVO4 photoanode synergized with nickel hydroxide cocatalyst for high-performance photoelectrochemical water splitting

BiVO4 is a promising photoanode material for converting solar energy into hydrogen fuel, but its practical applicability is primarily constrained by severe surface charge recombination and slow water oxidation processes. Here, the modification of BiVO4 surface by Cl− with appropriate electronegativity greatly promoted the photoelectric water oxidation activity. The Cl-BiVO4 electrode exhibited a photocurrent of 2.55 mA cm−2, at 1.23 V vs RHE. The research shows that the surface anion polarization of BiVO4 is helpful for trapping photogenerated holes and prolonging the electron lifetimes. Then, the cocatalyst Ni(OH)2 is anchored on Cl-BiVO4 by a simple impregnation method, and a high-performance photoanode Ni(OH)2/Cl-BiVO4 is successfully constructed. The photocurrent density of the composite photoanode is 4.33 mA cm−2 (1.23 V vs RHE), which is approximately 3.0 times that of pure BiVO4 (1.44 mA cm−2). Moreover, the initial potential is negatively shifted, and the ABPE, IPCE and charge separation efficiency are also significantly improved. This research presents a simple and effective strategy for producing low-cost, high-performance solar water decomposition catalysts.