BiVO4-Based Heterojunction Photocathode for High-Performance Photoelectrochemical Hydrogen Peroxide Production

Photoelectrochemical (PEC) cells provide a promising solution for the synthesis of hydrogen peroxide (H₂O₂). Herein, an integrated photocathode of p-type BiVO₄ (p-BVO) array with tetragonal zircon structure coupled with different metal oxide (MO_x, M = Sn, Ti, Ni, and Zn) heterostructure and NiNC cocatalyst (p-BVO/MO_x/NiNC) was synthesized for the PEC oxygen reduction reaction (ORR) in production of H₂O₂. The p-BVO/SnO₂/NiNC array achieves the production rate 65.46 μmol L^-1 h^-1 of H₂O₂ with a Faraday efficiency (FE) of 76.12%. Combined with the H₂O₂ generation of water oxidation from the n-type Mo-doped BiVO₄ (n-Mo:BVO) photoanode, the unbiased photoelectrochemical cell composed of a p-BVO/SnO₂/NiNC photocathode and n-Mo:BVO photoanode achieves a total FE of 97.67% for H₂O₂ generation. The large area BiVO₄-based tandem cell of 3 × 3 cm² can reach a total H₂O₂ production yield of 338.84 μmol L^-1. This work paves the way for the rational design and fabrication of artificial photosynthetic cells for the production of liquid solar fuel.