BiOI0.8-xF0.2 Solid Solutions with Suitable Surface Halogen Vacancies for Comprehensive and Enhanced Photocatalytic Performance

Bismuth oxyiodide (BiOI) is a highly promising material for photocatalytic degradation of pollutants, owing to its distinctive hierarchical and band structures. However, the poor photo-oxidation capability and fast recombination of photogenerated carriers constrain the application potential of BiOI. Introducing surface defects offers a compelling strategy for enhancing the photocatalytic performance. In this study, we develop BiOI 0.8- x F 0.2 solid solutions with optimal halogen vacancies, displaying excellent photodegradation efficiency for hazardous pollutants such as phenol, ciprofloxacin, tetracycline, and rhodamine B. Their photodegradation rates are 6.6, 25.1, 40.9, and 7.2 times higher than those of BiOI, respectively. The improved catalytic activity is primarily due to the appropriate band structure regulated by the solid solution of BiOF and BiOI, along with the favorable surface atomic state modified by halogen vacancies, which promotes charge separation and inhibits photogenerated carrier recombination. This study reveals the beneficial impact of halogen vacancies on photocatalytic performance and provides valuable insights into designing efficient and versatile photocatalysts.