Electronic structure modulation of covalent organic frameworks by single-atom Fe doping for enhanced oxidation of aqueous contaminants

A strategy for confining single-atom Fe in porous carbon ([email protected]) from covalent organic framework (COF) was proposed and the [email protected] catalysts were tested as peroxymonosulfate (PMS) activators for organic pollutants abatement. Iron doping preferentially generated effective single-atom Fe-Nx active sites into the carbon framework with electronic structure modulation, endowing prominent catalytic properties. Both in-situ electron paramagnetic resonance spectrometry and quenching measurements revealed that singlet oxygen (1O2) generated by the [email protected]/PMS system was primarily responsible for organic degradation rather than sulfate and hydroxyl radicals. The abundant single-atom Fe-Nx active sites with optimized binding energy were found to successfully activate PMS to produce 1O2, while the rich pyrrolic nitrogen may act as the adsorption site of organic molecules, giving rise to remarkable catalytic activity in a broad pH range. The present investigation offers a new strategy to the construction of various COF-immobilized catalysts for an efficient environmental cleanup.