Increasing the migration and separation efficiencies of photogenerated carriers in CQDs/BiOCl through the point discharge effect

Increasing the migration and separation efficiencies of photogenerated carriers can enormously enhance photocatalytic properties. Thus, a novel CQDs/BiOCl nanocomposite with rich oxygen vacancies (OVs) was effectively synthesized via a hydrothermal method by using maltitol as a carbon source to address these issues. The photocatalysts were characterized by XRD, SEM, TEM, FT-IR, BET, XPS, PL, EIS, I-t, DRS and ESR. The experimental results demonstrate that BOC-1 can purify 72% tetracycline hydrochloride (10 mg/L, TC-HCl) within 60 min, which is 4 times higher than pure BiOCl. Moreover, photocatalytic mechanism was thoroughly studied and verified that the cooperation of point discharge effect (PDE) and rational OVs concentration induced by carbon quantum dots (CQDs) can significantly enhance the migration and separation of photo-induced carriers, thereby leading to high photocatalytic activity of the as-prepared nanocomposites. In addition, the contribution of the free radicals was comprehensively calculated based on trapping experiments. the contributions of ·OH, ·O2- and 1O2 are 6.38%, 48.94% and 8.51%, respectively. This study provides a promising strategy to boosting the photoinduced carrier transfer properties by the coupling of point discharge effect and defect engineering.