Novel organic/inorganic PDI-Urea/BiOBr S-scheme heterojunction for improved photocatalytic antibiotic degradation and H2O2 production

The matched energy band structure and efficient carrier separation efficiency are the keys to heterogeneous photocatalytic reactions. A novel organic/inorganic step scheme (S-scheme) heterojunction PDI-Urea/BiOBr composite photocatalyst was constructed by simple solvothermal reaction combined with in-situ growth strategy. The composite photocatalyst not only has high chemical stability, but also can generate and accumulate a large number of active species (h+, •O2−, •OH, H2O2). PDI-Urea/BiOBr showed higher photocatalytic activity for the degradation of antibiotic such as ofloxacin (OFLO), tetracycline (TC) and the production of H2O2 in the spectral range of 400–800 nm. The apparent rate constant of 15% PDI-Urea/BiOBr for photocatalytic degradation of TC (or OFLO) was 2.7 (or 2.5) times that of pure BiOBr and 1.7 (or 1.8) times that of pure PDI-Urea. The H2O2 evolution rate of 15% PDI-Urea/BiOBr was 2.5 times that of PDI-Urea and 1.5 times that of BiOBr, respectively. This work has formed a mature S-scheme heterojunction design thought and method, which offers new visions for the development of heterogeneous photocatalysts.