Enhancing Z-scheme {001}/{110} junction in BiOCl with {110} Surface Oxygen Vacancies for Photocatalytic Degradation of Rhodamine B and Tetracycline

Since photocatalysis relies on surface reactions, the exposed facets and surface defects of the catalyst play important roles. In this study, we investigate the influence of oxygen vacancy creation on various exposed facets on the electronic structure and photocatalytic properties of {001}/{110}-bismuth oxychloride (BiOCl) with plate-like morphology prepared via a facile co-precipitation technique. Our experiments demonstrated that the ratio of different exposed facets could be controlled by adjusting HCl concentration in the precipitation process. Although the obtained BiOCl samples have a large band gap energy, oxygen vacancies (OV) induce defect states within the bandgap, enhancing the photocatalytic performance under visible light. Experiments and calculations have revealed that formation of OV is easier on the (110) facet than on the (001) facet. Consequently, the sample with a higher portion of (110) exposed facet exhibits higher OV. While {001}/{110} Z-scheme is created in all samples, higher OV enhance the work function difference (ΔΦ) between the two facets. As a result, an internal electric field is stronger, leading to improved carrier separation and photocatalytic degradation of Rhodamine B and Tetracycline. Therefore, this systematic investigation contributes to the advancement of understanding BiOCl photocatalysts and offers valuable insights for designing and optimizing photocatalytic materials for environmental remediation applications.