Fabrication of Fe2O3/BiVO4 heterojunction by doping method to improve the solar water splitting performance of BiVO4

Abstract

BiVO4 is widely used in the construction of photoanodes because of its narrow band gap, sufficient power for oxygen evolution at the valence band position and strong light absorption ability. It is a promising photoelectrochemical water splitting material. However, its electron migration ability is weak, the hole diffusion distance is short, and there is a serious charge recombination problem. Here, we report a composite photoanode with excellent photoelectric properties: Fe2O3/BiVO4, which was prepared by a simple doping method using BiVO4 photoanode as substrate. The formation of heterojunction between BiVO4 and Fe2O3 promotes carrier separation and transfer, and effectively increases carrier density. Simultaneously, Fe2O3 layer provides photocorrosion protection for BiVO4, which enhances the photoelectric performance and stability of BiVO4. In addition, at 1.23 V vs. RHE, the photocurrent density of the photoanode was 1.3 mA cm−2, 3.25 times that of the pure BiVO4 electrode, and the initial potential shifted negatively by 230 mV. Fe2O3/BiVO4 photoanode shows satisfactory photocurrent density, which provides a feasible scheme for the preparation of new heterogeneous photoanode.