Enhanced antibiotic degradation performance of Cd0.5Zn0.5S/Bi2MoO6 S-scheme photocatalyst by carbon dot modification

S-scheme heterojunction engineering is an effective strategy to attain distinctive photocatalysts. Herein, a carbon dots modulated S-scheme hetero-structured photocatalyst of Cd0.5Zn0.5S nanoparticles/Bi2MoO6 microspheres/carbon dots (CZCBM), aiming to conquer the photo-corrosion and strengthen the photocatalytic property of Cd0.5Zn0.5S, was developed via a facile solvothermal route. Under visible light, the optimal CZCBM-2 affords a 1.8-, 1.5-, or 0.6-time reinforcement in the oxytetracycline degradation rate constant compared to Bi2MoO6, Cd0.5Zn0.5S or Cd0.5Zn0.5S/Bi2MoO6, which is credited to the strengthened visible-light response, increased reactive sites, and efficient dissolution of photo-carriers with optimal redox capacity because of the co-effect of carbon dots and S-scheme heterostructure. Significantly, the photo-corrosion of Cd0.5Zn0.5S is significantly suppressed and CZCBM-2 affords superior stability and reusability during cycling tests. Besides, CZCBM-2 can be well adapted to various environments. The toxicology appraisement unravels the decreased eco-toxicity of most intermediates compared to oxytetracycline. Lastly, an S-scheme charge transfer mechanism with carbon dots as electron reservoir in CZCBM is deduced, which uncloses that •O2− and h+ dominantly account for oxytetracycline eradication and detoxification. This study demonstrates the design of unique carbon dots favored S-scheme heterostructures as an effective “Two Birds with One Stone” strategy to achieve high anti-photo-corrosion performance and reinforced photocatalytic performance of sulfides.