p-Type NiO modified BiVO4 photoanodes with enhanced charge separation and solar water oxidation kinetics

Bismuth vanadate is considered as a promising photoanode material for photoelectrochemical water splitting. However, the frequent bulk charge recombination and poor surface reaction kinetics restrict its performance in photoelectrochemical cell seriously. Herein, we developed a facile method to build a p-n heterojunction of NiO/BiVO4 with enhanced charge separation and surface reaction kinetics. The internal electric field of our heterojunction can improve the electron-hole separation efficiency from 51% to 65% at 0.6 VRHE. Moreover, the p-type NiO can significantly enhance the surface oxygen evolution reaction kinetics. Based on these synergistic effects, our NiO/BiVO4 photoanode achieved a high solar to hydrogen efficiency of 0.72% at 0.76 VRHE.