H₂O₂-driven reactive oxygen cascade in g-C₃N₄/Zn-MOF S-scheme heterojunctions for enhanced solar photocatalytic...

Efficient photocatalysts for solar-driven environmental remediation are urgently needed but remain limited by poor charge separation and insufficient reactive species generation. Herein, we report a novel g-C₃N₄/Zn-MOF (CN/Zn-MOF) S-scheme heterostructure synthesized via a rapid microwave-assisted hydrothermal method, enabling in-situ integration of g-C₃N₄ with a Zn-based metal-organic framework and strengthening interfacial coupling. The optimized CN/Zn-MOF exhibited nearly twice the tetracycline (TC) degradation efficiency of pristine g-C₃N₄ under simulated solar irradiation, owing to favorable band alignment, efficient photogenerated charge separation, and enhanced hydrophilicity. Notably, the CN/Zn-MOF heterojunction facilitated a two-step single-electron process for in-situ hydrogen peroxide (H₂O₂) production, which subsequently acted as a precursor for reactive oxygen species (ROS) such as singlet oxygen (¹O₂) and hydroxyl radicals (‧OH). This H₂O₂-mediated ROS cascade markedly boosted oxidative degradation performance. Furthermore, the CN/Zn-MOF photocatalyst exhibited high efficacy in treating real printing and dyeing wastewater, effectively removing organic pollutants and reducing aquatic toxicity. This work offers a versatile interfacial engineering strategy for multifunctional photocatalyst design and highlights the pivotal role of H₂O₂-driven ROS cascades in advanced environmental purification.