Enhancing the separation efficiency of photo-induced carriers in a Bi2S3/BiOCl heterostructure by cooperative influence of oxygen vacancies and the interfacial electric field

Enhancing the photocatalytic performance via improving the separation efficiency of photo-induced carriers is a promising strategy. Here, a type-II Bi2S3/BiOCl heterostructure was successfully fabricated by an ultrasound method to tackle this issue. The experimental results revealed that BiS/BOC-4 can purified 89% TC-HCl (20 mg L−1, k = 0.0627 min−1) in 30 min, which was 2.6 and 5.5 fold larger than BiOCl (k = 0.0245 min−1) and Bi2S3 (k = 0.0113 min−1), respectively. Moreover, the mechanism behind the improved photocatalytic activity was derived from the good light-utilization efficiency, eminent adsorption ability, and excellent separation efficiency of the carriers induced by the coupling of the oxygen vacancies (OVs) and the interfacial electric field (IEF). Simultaneously, the structure–activity relationship between the photocatalytic performance and the concentration of OVs was established via the response surface methodology. This work not only provides a promising strategy to ameliorate the photocatalytic activity by syngestic vacancy engineering and heterostructure engineering, but also offers a new angle to understand the relationship between defects and the activity.