Efficient peroxymonosulfate activation by copper-nitrogen co-doped porous carbon nanosheet catalyst

This research designed a copper and nitrogen co-doped porous carbon nanosheets (Cu–N/C) and systematically explored its efficient application in peroxymonosulfate (PMS) activation. The Cu–N/C catalyst, prepared using a multi-step anchoring strategy, exhibited remarkable catalytic activity, benefiting from its large specific surface area and uniformly distributed Cu–N coordination structure. This structure notably improved PMS activation, enabling the effective breakdown of organic pollutants like phenol. Experimental results demonstrated that 0.5 mmol of Cu–N/C catalyst achieved complete phenol removal in the PMS system, maintaining strong catalytic performance over a broad pH range. Through radical quenching experiments and EPR analysis, superoxide radicals were predominant in the reaction, while non-radical mechanisms, such as high-valence copper species and direct electron transfer, contributed to pollutant degradation. Additionally, pyrrolic nitrogen sites and surface hydroxyl groups were identified as key active sites, effectively adsorbing and activating PMS. The introduction of copper-induced defects further enhanced PMS activation, while pyrrolic nitrogen sites adsorbed pollutants, improving phenol degradation efficiency. Three-dimensional fluorescence spectroscopy and gas chromatography-mass spectrometry analysis identified hydroquinone, catechol, resorcinol, and p-benzoquinone as intermediate products during phenol degradation. The catalytic performance was restored through thermal treatment. This research provides new insights and theoretical support for PMS activation and organic pollutant degradation.