A CuFe-PCN single-atom catalyst with highly dense diatomic sites for alkaline Fenton-like decontamination

Abstract

Although decontaminating organic wastewater by alkaline Fenton-like reactions is highly cost-effective, the challenge lies in the fabrication of highly efficient catalysts to accelerate H₂O₂ conversion into reactive oxygen species (ROS). Herein, an in situ polymerization strategy was presented to fabricate a highly dense diatomic CuFe-PCN catalyst by anchoring CuN₃ and FeN₃ sites into polymeric carbon nitride with loadings as high as 12.5 wt% and 10.6 wt%, respectively. CuFe-PCN showed high efficiency to convert H₂O₂ into ¹O₂ in alkaline solutions for methyl orange degradation with a rate constant of 0.656 min⁻¹. Experiments and DFT calculations reveal that CuN₃ sites function as the active centers, and synergy between CuN₃ and FeN₃ sites boosts the intrinsic activity of CuN₃ sites by up-shifting the d-band center, decreasing charge density, improving H₂O₂ adsorption, and decreasing activation energy. As a result, highly dense CuN₃ sites with enhanced intrinsic activity realize efficient and directional conversion of H₂O₂ into ¹O₂ for alkaline organic wastewater degradation. CuFe-PCN catalyzed alkaline Fenton-like reactions also demonstrate applications in degrading high-salinity antibiotic wastewater and practical livestock urine wastewater. Our findings pave a new way to efficiently activate H₂O₂ to generate ¹O₂ in alkaline solutions for potential applications in cost-effective organic wastewater decontamination.