Constructing S-scheme 3D Zn₃In₂S₆/ReS₂ heterojunction photocatalyst for simultaneous organic pollutants degradation and hydrogen production

Controlling efficient interfacial charge transfer is crucial for developing advanced photocatalysts. This study successfully developed a bifunctional photocatalyst with an S-scheme heterojunction by incorporating ReS₂ into the Zn₃In₂S₆ (ZIS) nanoflower structure, enabling the organic pollutants degradation and synergistic hydrogen production. The optimized ZIS/ReS₂-1% exhibited exceptional photocatalytic efficiency, reaching a 97.7% degradation rate of ibuprofen (IBP) within 2 h, along with a hydrogen generation rate of 1.84 mmol/g/h. The degradation efficiency and hydrogen generation rate were 1.78 and 5.75 times greater than that of Zn₃In₂S₆, respectively. Moreover, ZIS/ReS₂-1% demonstrated excellent catalytic degradation abilities for various organic pollutants such as ciprofloxacin, amoxicillin, norfloxacin, levofloxacin, ofloxacin, sulfamethoxazole, and tetracycline, while also showing good synergistic hydrogen production efficiency. Electron spin resonance and radical scavenging experiments verified that h⁺, ·O^2-, and ·OH were the primary reactive species responsible for IBP degradation. The superior photocatalytic performance of the ZIS/ReS₂-1% was mainly attributed to its broad and intense absorption of visible light, effective separation of charge carriers, and enhanced redox capabilities. The degradation pathway of IBP was unveiled through Fukui function and liquid chromatography-mass spectrometry, and the toxicity of the degradation intermediates was also examined. In-situ XPS and density functional theory (DFT) calculations confirmed the existence of S-scheme heterojunction. This study provided a new pathway for simultaneously achieving organic pollutant treatment and energy conversion.