Boosting photoelectrocatalytic hydrogen evolution of Bi@OV-BiOBr/Cu3P high-low heterojunction with dual-channel charge transfer

A high-low heterojunction composite, oxygen vacancies BiOBr induced Bi precipitation Bi@OV-BiOBr/Cu3P with Bi-O-P chemical bond, was synthesized using a solvothermal method. Compared to single substance, the carrier lifetime and separation rate of Bi@OV-BiOBr/Cu3P were significantly improved. According to theoretical calculations and experimental results, Cu3P can be considered as a hole extractor to accelerate the separation of photogenerated carriers. The successful construction of Bi@OV-BiOBr/Cu3P high-low heterojunction with Bi metal can not only activate water molecules and reduce the dissociation energy barrier of water, but also separate and retain the highly reductive electrons. Bi metal and Cu3P with low valent play a crucial role in dual-channel charge transfer. Bi@OV-BiOBr/Cu3P exhibits the highest hydrogen evolution rate up to 723.85 μmol·cm−2·h−1. It also displays excellent photoelectrocatalytic hydrogen production stability. The boosting hydrogen production activity and stability of Bi@OV-BiOBr/Cu3P are attributed to the construction of high-low heterojunctions and the dual-channel charge transfer mechanism.