Constructing S-scheme heterojunctions through electrostatic self-assembly of Co3O4 quantum dots and CuBr for photocatalytic hydrogen evolution

Abstract

Utilizing solar energy to power semiconductors for water splitting and hydrogen production is an effective method for clean energy generation. This study presents a new S-scheme heterojunction catalyst, constructed via electrostatic self-assembly of CuBr and Co3O4 quantum dots. The band gap-matching positions and energy band structures of CuBr and Co3O4 quantum dots are well-suited for this purpose. The hydrogen precipitation performance of the resulting CQCB2 catalyst is approximately four times higher than that of a single catalyst. Additionally, CQCB2 exhibits good stability, with an 80% hydrogen precipitation efficiency after four consecutive cycles. The study demonstrates that CQCB2 exhibits a high absorbance intensity, efficient charge separation, low electron transport resistance, and low photogenerated carrier recombination rate. This is further validated by XPS and UPS experiments, which support the S-scheme heterojunction charge transfer mechanism. Overall, this paper provides a unique insight into the study of S-scheme heterojunction catalysts.