Mechanism insight into boosting photocatalytic purification of tetracycline hydrochloride over 2D/2D S-scheme (BiO)2CO3/BiOCl heterojunctions

The (BiO)2CO3/BiOCl heterojunction holds promise for photocatalytic purification of antibiotics, which is primarily attributed to the type-II and Z-scheme photocharge separation mechanisms. However, it lacks a report on S-scheme heterojunction for efficiently promoting photocharge separation and retaining powerful redox capability. In this study, a 2D/2D S-scheme (BiO)2CO3/BiOCl (denoted as (BC/BL)1) heterojunction was prepared through the hydrothermal synthesis method. The as-synthesized (BC/BL)1 exhibited a significantly enhanced photocatalytic activity, with a degradation rate of tetracycline hydrochloride (TC-HCl) reaching 95.3% after 60 minutes. Its kinetic constant of photodegradation surpassed that of (BiO)2CO3 and BiOCl by 20.8 and 3.8 times, respectively. A series of characterizations revealed that the improved photocatalytic activity of the (BC/BL)1 sample stemmed from the formation of a built-in electric field at the intimate interface, which strongly drove the photogenerated carriers to achieve the S-scheme separation. This study highlights the potential application prospects of photocatalyst (BC/BL)1 in antibiotic degradation.