Monoatomic Copper Anchored on Tubular Carbon Nitride with High Carbon/Oxygen Abundance via 2-Methylimidazole Direction: Synthesis and Catalytic Performance

In this study, the Cu-SA/g-C3N4@2MI(2) catalyst was synthesized using a preassembly strategy, briefly, dimethylimidazole acts as a structure-directing agent to disperse and immobilize copper in the carbon nitride precursor through bridging.. Subsequently, this catalyst was combined with H2O2 to construct a non-homogeneous phase-like Fenton reaction system for the treatment of RhB wastewater. The microscopic morphology and physicochemical properties of the catalyst was characterized by SEM, TEM, XRD, FTIR and XPS. The results show that Cu-SA/g-C3N4@2MI(2) exhibits a tubular structure with a specific surface area to 77.15 m2/g, and the presence of copper in the Cu + form. The Cu-SA/g-C3N4@2MI(2) catalyst exhibited the maximum Fenton-like catalytic performance under neutral conditions, with 94.5% degradation of 50 mg/L RhB within 1h. The catalyst maintains excellent catalytic performance in a wide pH range (3–11) and has good stability after being recycled for 5 times. The free radical trapping experiments and EPR results showed that 1O2 and O2•⁻ were the main active substances in the degradation process. Based on the characterization analysis and experimental results, a possible pre - assembly strategy for synthesizing the catalyst and the pollutant degradation mechanism are proposed. This innovative synthesis strategy of transition metal doped carbon nitride catalysts based on imidazole ligands provides a new method for rational design of efficient H2O2 activation systems with clear active sites, and establishes a theoretical model basis for the study of metal-nitrogen coordination regulation degradation mechanisms.