Mechanism of peroxymonosulfate activation by nanoparticle Co@N-C: Experimental investigation and theoretical...

The release of organic dyes, such as Rhodamine B (RhB), into industrial wastewater has led to significant issues with color pollution in aquatic environments. Herein, we prepared a cobalt nanoparticles (NPs)-based catalyst with the nitrogen-doped carbon-support (Co@N-C) for effective PMS activation. The Co@N-C/PMS system demonstrated the excellent catalytic activity of Co@N-C for activating PMS, achieving nearly 100% degradation of RhB. Singlet oxygen (¹O₂) and sulfate radicals (SO₄•^-) were dominant reactive oxygen species for RhB degradation. Density functional theory (DFT) calculations substantiated that the production of ¹O₂ commenced with the initial generation of *OH through hydrogen abstraction from PMS, culminating in the direct release of oxygen to form ¹O₂ (PMS→*OH→O*→¹O₂). The generation of SO₄•^- was attributed to electron transfer to PMS from the surface of Co NPs (Co⁰→Co²⁺→Co³⁺) and the C-N shell (Co²⁺→Co³⁺). The research findings provided new insights into the development of Co-based heterogeneous catalysis for advanced oxidation of refractory organic pollutants in wastewater treatment.