Sustainable Photocatalysis: Waste PET-Derived Zn Coordination Polymer/Carbon Nitride Composite for Green Hydrogen Peroxide Synthesis

This study successfully constructed a Zn-CP/CN composite by integrating carbon nitride (CN) with a Zn coordination polymer (Zn-CP) synthesized from terephthalic acid (TPA), a hydrolysis product of waste polyethylene terephthalate (PET). This composite enables green hydrogen peroxide (H₂O₂) synthesis under visible-light irradiation. FT-IR and XPS results show that the Zn-O coordination signal is retained after composite formation, while the interaction between CN and the aromatic TPA backbone induces interfacial electronic redistribution in the Zn coordination environment. The π–π stacking interaction between TPA and CN further facilitates the separation and migration of photogenerated electrons and holes, enhancing photocatalytic efficiency. Oxygen adsorption experiments revealed that Zn-CP/CN exhibited an adsorption capacity of 10.2144 cm³/g (STP), significantly higher than CN (4.1563 cm³/g). Under visible light (λ > 420 nm), Zn-CP/CN produced 4.94 μmol of H₂O₂ within 1hour, outperforming CN (3.07 μmol) and Zn-CP (2.27 μmol). This strategy not only markedly improves the photocatalytic performance of carbon nitride-based materials but also provides a sustainable pathway for the valorization of waste PET.