In-situ construction of oxygen-deficient BiOCl/Bi2O2CO3 heterojunction photocatalyst for antibiotic treatment

Antibiotic pollution has been shown to cause water and soil contamination, leading to the development of multi-drug-resistant bacteria, which in turn affects human health. Photocatalytic degradation of antibiotics is a well-established green technology. In this paper, an oxygen-deficient BiOCl/Bi 2 O 2 CO 3 heterojunction photocatalyst was designed, synthesised and characterised. The experimental results showed that the BiOCl/Bi 2 O 2 CO 3 composite catalyst synergized with PMS for the degradation of tetracycline at high concentration (40   mg·L -1 ) eliminated 80% of the antibiotic in only 60   min, and its main active radicals were ·OH and ·O 2 - . The intermediates of tetracycline degradation were detected by LC-MS and their toxicity was evaluated based on quantitative structure-effect relationship (QSAR). It was found that the TC toxicity was significantly reduced. In addition, BiOCl/Bi 2 O 2 CO 3 exhibited good stability in the cyclic operation of photocatalytic degradation of TC, showing its potential as an efficient photocatalyst. The in-situ construction of BiOCl/Bi 2 O 2 CO 3 heterojunctions as well as the formation of oxygen defects facilitated the effective separation of photogenerated carriers, which led to the improvement of photocatalytic performance. The catalytic degradation mechanism of TC was also explored. This study provides an idea for the construction of stable and efficient Bi-based heterojunction photocatalysts with oxygen defects.