Architecting coordination polymer-derived cobaltic hybrids with carbon-nitride domains in a carbon nanotube aerogel for efficient oxone activation

Abstract

Carbon-based catalysts incorporating cobalt species have been widely explored for Oxone activation toward the degradation of emerging contaminants. Among them, CNT-reinforced carbon aerogels are attractive due to their interconnected porosity, high electrical conductivity, and tunable surface chemistry. However, achieving uniform incorporation of cobalt domains within such aerogels remains challenging, particularly when simultaneously introducing oxide-, sulfide-, and nitrogen-associated functionalities. In this work, a cobalt coordination polymer derived from a sulfur-and nitrogen-containing ligand was grown in situ within a CNT-carbon aerogel framework and subsequently carbonized to obtain a multi-component catalyst, CoCNTCA. The resulting material integrates cobaltic hybrid domains, carbon-nitride functionalities, and a conductive CNT-carbon network, providing a favorable platform for Oxone activation. CoCNTCA exhibits substantially enhanced PSA degradation compared with its precursor materials, with reaction kinetics dependent on catalyst and Oxone dosages and showing reasonable tolerance toward co-existing ions and natural water matrices. Scavenger experiments indicate the involvement of both radical (SO4 center dot-, center dot OH, O2 center dot-) and non-radical (1O2) pathways. XPS analyses of fresh and spent catalysts reveal cobalt redox cycling and the participation of sulfur-and oxygen-related surface species during catalysis. In addition, DFT calculations identify the most reactive aromatic and heteroatom-containing sites on PSA, while LC-MS analyses support a degradation pathway involving aromatic oxidation, ring opening, and sequential fragmentation. This study presents a structurally engineered strategy for constructing efficient Oxone activators and provides mechanistic insight into the degradation of nitrogen-and sulfur-containing emerging contaminants.