A novel S-scheme heterojunction of Cd0.5Zn0.5S/BiOCl with oxygen defects for antibiotic norfloxacin photodegradation: Performance, mechanism, and intermediates toxicity evaluation

• Published in: Journal of colloid and interface science 2023-01, Vol.629, p.276-286
• Main Authors: Cai, Mingjie, Liu, Yanping, Dong, Kexin, Wang, Chunchun, Li, Shijie
• Format: Article
• Language: English
• Subjects: Antibiotic degradation; Cd0.5Zn0.5S/BiOCl; Oxygen vacancy; S-scheme; Toxicity analysis; Visible-light photocatalysis
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2022.08.136

A novel S-scheme heterojunction of Cd0.5Zn0.5S nanodots/OVs-rich BiOCl microspheres was designed for highly improved visible-light photo-degradation of pharmaceuticals. [Display omitted] •A brand-new Cd0.5Zn0.5S/OV-rich BiOCl S-scheme heterojunction was designed.•Cd0.5Zn0.5S/OV-rich BiOCl demonstrates highly upgraded photocatalytic activity and stability.•The norfloxacin degradation routes and the bio-toxicity evolution were unclosed.•The S-scheme charge transfer mechanism and OVs boosts the improved charge separation and strengthened redox power. 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 Cd0.5Zn0.5S 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 Cd0.5Zn0.5S. As a result, Cd0.5Zn0.5S/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 Cd0.5Zn0.5S or BiOCl. Cd0.5Zn0.5S/BiOCl also shows good resistance to alkaline, sodium salts and humic acid. The performance of Cd0.5Zn0.5S/BiOCl to photocatalytically degrade other PPCPs with different molecular structures was further confirmed. At last, the ability of Cd0.5Zn0.5S/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.