Boosting catalytic performance of N doped porous carbon derived from coal tar pitch: The role of N species and the contribution of 1O2

Abstract

In this study, nitrogen-doped carbon material (N-PC-d) derived from coal tar pitch using dicyandiamide as N source was successfully synthesized, exhibiting outstanding catalytic performance in the activation of peroxymonosulfate (PMS) for the degradation of Orange G (OG). By optimizing key parameters such as PMS dosage, N-PC dosage, nitrogen source, pH, anions, and PS source, the optimal N-PC-d/PMS system achieved a degradation rate 1.45 times higher than that of the PC/PMS system within a broad pH range (2.0–10.0). Through electron paramagnetic resonance (EPR) and quenching experiments, it was found that singlet oxygen (¹O₂) was the predominant species accountable for OG degradation, while reactive oxygen species (ROS), including superoxide (O₂^·-), hydroxyl radicals (·OH), and sulfate radicals (SO₄^·-), played auxiliary roles. Moreover, the structure–activity relationship analysis revealed that functional groups such as CC, CO, and pyridine N were mainly involved in PMS activation. The degradation mechanism of OG was further elucidated by high-performance liquid chromatography-mass spectrometry (HPLC-MS). This research presented a cost-efficient N-doped porous carbon material for environmental remediation and provides more profound insights into the mechanisms of PMS activation by N doped carbon-based materials.