Integration of oxygen vacancies into BiOI via a facile alkaline earth ion-doping strategy for the enhanced photocatalytic performance toward indometacin remediation

Highlights: • A novel visible-light-driven SrBiOI photocatalyst along with OVs was prepared via a convenient process. • The photocatalyst showed enhanced photocatalytic activity in IDM degradation. • The roles of reactive species and degradation mechanism were identified during the photocatalytic process. • HRAM LC-MS/MS and ALIE calculation helped to explain the degradation pathways. Bismuth oxyiodide (BiOI) has garnered intense attention in the field of photocatalysis for environmental remediation; however, it suffers from a high electron-hole recombination rate. In this study, for the first time, we report on a facile strategy for the creation of oxygen vacancies in BiOI via strontium (Sr²⁺) doping. The as-prepared 0.45-SrBiOI demonstrated significantly enhanced photocatalytic degradation of indometacin under visible light exposure, which was almost 10 folds higher than pristine BiOI. This augmented photocatalytic performance was ascribed to the accelerated separation of charge carriers by oxygen vacancies, as well as Sr ion trapping electrons. Reactive species determination experiments revealed that O₂^▪−, ¹O₂, and h⁺ were the dominant active species. Finally, potential indometacin degradation pathways were proposed based on the identification of degradation by-products and theoretical calculations. This study offers new perspectives for the synthesis of highly efficient and cost effective BiOI-based photocatalysts, and provides a promising strategy toward advanced environmental remediation.