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

摘要

A strategy for confining single-atom Fe in porous carbon (Fe@COF) from covalent organic framework (COF) was proposed and the Fe@COF 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 (~1O_2) generated by the Fe@COF/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 ~1O_2, 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.