Enhanced photocatalytic degradation of 2-chlorophenol over Z-scheme heterojunction of CdS-decorated oxygen-doped g-C3N4 under visible-light

Constructing photocatalysts with outstanding visible light utilization efficiency and a high-efficiency photo -generated charge transfer rate is the key to the photodegradation of organic pollutants in wastewater. Oxygen -doped graphitic carbon nitride (g-C3N4) responsive to a broad visible light range was prepared, to which CdS nanoparticles (NPs) were anchored to fabricate a Z-scheme heterojunction, constructing abundant charge transport orbitals that facilitate interfacial photo-generated charge separation. Meanwhile, density functional theory (DFT) calculations and electron spin resonance (ESR) tests proved that oxygen-doped g-C3N4/CdS-3 (O-CN/CdS-3) followed the Z-scheme charge transfer mechanism. The results showed that O-CN/CdS-3 degraded 10 ppm of 2-chlorophenol (2-CP) within 60 min, with a degradation rate constant (k = 0.10832) of around 11.5-fold that of g-C3N4 (0.00945). Furthermore, the active species and main intermediate products were also studied to explore the possible degradation pathway of 2-CP. Overall, this strategy provides insight for constructing other Z -scheme heterojunction photocatalysts for the efficient degradation of CPs.

Automated summary

Constructing photocatalysts with excellent visible light utilization efficiency and high-efficiency photo-generated charge transfer rate is crucial for the photodegradation of organic pollutants in wastewater. In this study, oxygen-doped graphitic carbon nitride (g-C3N4) was prepared and used as a responsive material for a wide range of visible light. CdS nanoparticles were then anchored onto the g-C3N4 to form a Z-scheme heterojunction, which facilitated interfacial charge separation. The results showed that the oxygen-doped g-C3N4/CdS-3 displayed a significantly higher degradation rate for 2-chlorophenol compared to g-C3N4.