Nitrogen-Coordinated Cobalt Embedded in a Hollow Carbon Polyhedron for Superior Catalytic Oxidation of Organic Contaminants with Peroxymonosulfate

The search for high-active and long-lasting materials is of paramount significance for elimination of aqueous organic contaminants. Herein, a nitrogen-coordinated cobalt embedded in hollow carbon polyhedron (marked as NCoHCP) has been synthesized by thermal transformation of core-shell-architectured ZIF-8@ZIF-67. X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and theoretical calculations confirmed the coordination of a Co atom with one N atom in NCoHCP. The resultant NCoHCP catalyst delivers extremely superior catalytic performance in peroxymonosulfate (PMS) decomposition into active species toward complete oxidation of organic pollutants in less than 45 s. Experimental data and theoretical computations disclosed the formation of Co-pyridinic N moiety not only creates the Co species with higher electron density as active sites but also increases the C atom neighboring pyridinic N with lower electron density as binding sites for PMS conversion toward reactive oxygen species generation to oxidize organic pollutant. On the other hand, the donation of electron from organic contaminant toward the C atom adjacent to pyridinic N also induces organic contaminant oxidation. The dual-pathway degradation contributes to superior catalytic oxidation of organics over NCoHCP. This study furnishes an effective strategy for developing high-performance and robust metal/carbon hybrid materials toward wide environmental applications.