Designing Highly Efficient Z-Scheme BiOCl/BiOI Heterojunctions and Oxygen Vacancy-Rich BiO(Cl,I) Solid Solutions for Visible-Light-Driven Mineralization of Aqueous Pollutants

Hierarchical BiOCl/BiOI and BiO(Cl,I) photocatalysts were obtained via a solution-phase reaction for visible-light-driven elimination of aqueous pollutants, where the phase/morphology evolution, relationship between energy band/microstructure structure and photocatalytic properties, and photoreaction mechanism can be deciphered in detail. It was well-documented that the R = 8:1 BiOCl/BiOI heterojunctions with a coherent interface of Bi and O atoms showed a relatively strong redox capacity owing to their rapid Z-scheme charge transfer and large interfacial contact and eventually degraded ∼92.52% and 96.57% of rhodamine B (RhB) and tetracycline (TC) molecules under 10 min of visible light irradiation, which was larger than those of bare BiOCl and BiOI. However, their poor photocatalytic stability was proved to be unfavorable to practical applications. The best BiOCl0.88I0.12 solid solutions separately elucidated the optimal RhB and TC removal efficiency of ∼99.97% and 97.54% after 10 and 6 min of illumination, and it still maintained a high photodegradation efficiency toward RhB after five consecutive runs. The exceptional photocatalytic performance is cogoverned by the characteristics of in situ generated oxygen vacancies and defect energy levels.