A novel S-scheme heterojunction of CdZnS/BiOCl with oxygen defects for antibiotic norfloxacin photodegradation: Performance, mechanism, and intermediates toxicity evaluation.

S-scheme heterojunction structure can endow the photocatalysts with high-performance photo-degradation of pharmaceuticals and personal care products (PPCPs) since it can remain the photogenerated electrons/holes with stronger redox ability. Herein, an integrative S-scheme heterojunction photocatalyst building from CdZnS nanoparticles and BiOCl microflowers with oxygen vacancies (OVs) was developed. Moreover, the in-situ grown process ensures the firm contact and intense electron coupling between BiOCl and CdZnS. As a result, CdZnS/BiOCl exhibited a significant reinforcement of photo-activity and stability for the abatement of antibiotic norfloxacin, manifesting a 2.8-fold or 9.6-fold enhancement compared to pristine CdZnS or BiOCl. CdZnS/BiOCl also shows good resistance to alkaline, sodium salts and humic acid. The performance of CdZnS/BiOCl to photocatalytically degrade other PPCPs with different molecular structures was further confirmed. At last, the ability of CdZnS/BiOCl for PPCPs de-toxicity was verified by evaluating the toxicity of norfloxacin and its degradation intermediate. This study demonstrates a new S-scheme heterojunction photocatalyt for efficient removal of PPCPs as well as provides some insights into developing high-performance metal sulfide solid-solution-based S-scheme heterojunctions for water decontamination.