Synergistic Chiral Mediation and Ga³⁺ Doping Introduces Lattice Distortion and Defect States to Construct Intensified Built-in Electric Field and Abundant Active Sites for Enhanced BiOBr Photoelectrocatalytic Performance

Abstract

The practical application of bismuth oxybromide (BiOBr) as a photoelectrocatalytic material is constrained by rapid charge carrier recombination and insufficient active sites. This paper for the first time employs chiral mediation coupled with Ga³⁺ doping to introduce lattice distortion and defect states into BiOBr, thereby enhancing the built-in electric field and expanding active sites for improved photoelectrocatalytic performance. The results demonstrate that at 1.23 V vs. RHE, the optimal samples with different chiral inducers achieved photocurrent densities of 0.374 mA/cm² and 0.336 mA/cm², representing approximately 1.94-fold and 2.11-fold enhancements compared to their undoped counterparts (0.193 mA/cm² and 0.159 mA/cm²), respectively. The performance improvement originates from the synergetic effect-induced lattice distortion that significantly strengthens the built-in electric field, thereby effectively promoting the separation of photogenerated charge carriers.Concurrently, the high-density surface defects introduced by this approach provide abundant active sites, further optimizing the interfacial reaction kinetics. However, excessively high doping concentrations lead to defect overload, transforming them into charge recombination centers that consequently aggravate carrier recombination and impede charge transport, leading to a decline in photocurrent density. This work provides a novel approach to address the prevalent challenges of rapid charge recombination and scarce active sites in photoelectrocatalytic materials.