Study on the synthesis of heterojunction Cu<sub>2</sub>O-BiVO<sub>4</sub> catalysts for the photoelectrochemical water splitting

Photoelectrochemical water splitting to convert solar energy into chemical energy stored in hydrogen fuel is a challenging task. In this work, BiVO4 was synthesized by the hydrothermal method. Cu2O was incorporated with BiVO4 by the reduction of Cu2+ with ascorbic acid on the BiVO4 particles, varying the Cu:Bi ratio in the reaction and reaction time. The prepared samples were characterized by XRD, SEM and UV-Vis DRS. Cu2O was formed with a low content and was well dispersed on the surface of BiVO4. The synthesized Cu2O-BiVO4 can absorb radiation in both UV and vision ranges with a wavelength less than 465 nm. The incorporation of Cu2O and BiVO4 can lead to an increase in the photocatalytic performance of the materials with both higher photogenerated current density and dark current density. The 3:10 Cu:Bi ratio in the reaction mixture is considered the optimum ratio for better photoelectrochemical activity of the synthesized catalyst.