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

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 (O) and sulfate radicals (SO•) were dominant reactive oxygen species for RhB degradation. Density functional theory (DFT) calculations substantiated that the production of O commenced with the initial generation of *OH through hydrogen abstraction from PMS, culminating in the direct release of oxygen to form O (PMS→*OH→O*→O). The generation of SO• was attributed to electron transfer to PMS from the surface of Co NPs (Co→Co→Co) and the C-N shell (Co→Co). The research findings provided new insights into the development of Co-based heterogeneous catalysis for advanced oxidation of refractory organic pollutants in wastewater treatment.