CAU-17-derived hollow tubular BiOX solid solution with oxygen vacancy: Optimized morphology and enhanced charge separation efficiency

To overcome the limitations of insufficient active sites and rapid charge recombination in conventional bismuth oxyhalide (BiOX) photocatalysts, we developed a novel CAU-17-derived strategy for constructing hollow tubular BiOX solid solutions with oxygen vacancies (OVs). The confined chemical environment in the CAU-17 precursor provides favorable conditions for the preparation of OVs-enriched BiOX solid solutions via a one-pot, low-temperature halogenation method. This method is applicable to the preparation of diverse BiOX solid solutions like BiOCl x Br 1-x and BiOBr x I 1-x . The CAU-17 halogenation simultaneously endows BiOX solid solutions with a hollow tubular architecture, an enhanced specific surface area, and residual organic carbon. The embedded carbon establishes conductive pathways that significantly enhance the migration efficiency of charge carriers. Importantly, the formation of solid solution can strengthen the intensity of inherent IEF between [X m ] layer and [Bi 2 O 2 ] layer, thereby enhancing the driving force for carrier separation. OVs, as electron traps, also contribute to improve the carrier separation efficiency. The hollow tubular structure and favorable carrier separation efficiency collectively empower OVs-BiOCl 0.5 Br 0.5 /C with superior visible-light activity, impressively degrading 90 % of Rhodamine B within 60 min primarily through •O 2 - and h + active species. This work supplies a versatile MOF-derived approach for the synthesis of hollow tubular BiOX solid solution with oxygen defect as high performance photocatalyst.