Bismuth-rich bismuth oxyhalides: a new opportunity to trigger high-efficiency photocatalysis

Abstract

As the continuation and advances in traditional BiOX (X = Cl, Br, I), bismuth-rich bismuth oxyhalides (Bi_aO_bX_c) show distinct differences in the surface local atomic structure, electronic structure, optical properties, and electrical conductivity relative to BiOX. These features endow bismuth-rich Bi_aO_bX_c with more tunable properties to achieve excellent photocatalytic performance. Here, the state-of-the-art progress in bismuth-rich bismuth oxyhalides is reviewed to clarify the key structure–activity relationship for enhanced photocatalytic performance. Various methods for the controllable synthesis and formation mechanism of bismuth-rich Bi_aO_bX_c are presented. Different strategies to tailor the photocatalytic behaviors are summarized, namely thickness tuning, morphological control, heteroatom doping, surface defect engineering, single atom engineering, surface modification, preparation of a solid solution and engineering of semiconductor heterojunctions. Moreover, the recent advances in Bi_aO_bX_c for diversified photocatalytic applications, such as H₂ generation, O₂ production, CO₂ reduction, N₂ reduction, organic synthesis and pollutant removal, are summarized. Finally, the existing challenges and perspectives are also presented to bring about new opportunities for future research.