Chlorella microsphere bio-template synergistically enhances the performance and mechanism of ZnCdS for the photocatalytic degradation of norfloxacin

This study used a solvothermal method to prepare chlorella microspheres (ZCS-Ch) loaded with carbon-hybridized, nitrogen-oxygen-doped Zn 0.3 Cd 0.7 S (ZCS) nanoparticles, employing Chlorella (Ch) as a biological template. The catalyst's morphology and structure were characterized using XRD, SEM, and XPS. Under simulated visible light, the catalyst effectively degraded Norfloxacin (NOR). Experimental results show that the photocatalytic activity of the nanocomposite is greatly enhanced. ZCS-Ch8 achieved a 92.3% NOR degradation rate within 1 h, with a degradation rate of 0.04198 min-1, which is 1.6 and 15.6 times higher than ZCS (0.02963 min −1 ) and Ch (0.00269 min −1 ) respectively. The increased photocatalytic activity was examined through photoelectrochemical characterization. The addition of Ch effectively promoted charge transfer of photogenerated carriers and reduced their recombination. Finally, radical scavenging experiments and electron spin resonance (ESR) techniques confirmed that superoxide radical (·O 2 - ) is the main active species. Additionally, the catalyst showed excellent cycling stability over five consecutive degradation tests.