Single-atom iron catalysts on defect-rich nitrogen-doped carbon nanosheets for efficient phenol degradation via peroxydisulfate activation

• • Fe/N–C catalyst achieves >98% phenol degradation within 30 min and 60% TOC removal, demonstrating superior performance for refractory pollutant treatment in coking wastewater. • • The catalyst features a high defect density (sp3-C/sp2-C = 0.66) and atomically dispersed iron, which are critical for enhancing PDS activation and electron transfer. • • Singlet oxygen (1O2) is identified as the primary reactive oxygen species, with both radical and non-radical pathways contributing to degradation, offering a robust mechanism for various organic pollutants. • • The synthesis uses coal-tar pitch, a low-cost by-product, enabling high-value conversion and aligning with circular economy principles, potentially reducing catalyst costs for industrial water treatment.