Engineering electronic and geometric structures of Fe, N-doped carbon polyhedrons toward organic contaminant oxidation

A universal gas diffusion strategy was developed to derive highly efficient PMS-activation catalysts com-prising isolated Fe atoms coordinated with N species embedded in carbon polyhedrons (Fe-NC). Their electronic and geometric structures were modulated by altering the precursor ratio and calcination tem-perature. Benefiting from the maximized atomic utilization, the obtained catalysts exhibited superior cat-alytic performances, outperforming almost all previously reported metal materials. The enhanced activity is likely due to an optimal particle size and Fe content, favorable Fe-Nx active sites, and conductive carbon materials. Scavenging and probing experiments indicated that surface Fe-NC and the defective edges with oxygen functional groups were the active sites for PMS activation to produce surface-bonding active com-plexes (Fe-NC-PMS) and high-valent iron oxo species (Fey = O) for organic degradation, unlike the reported radicals and singlet oxygen mediated degradation. Overall, this work provides a universal gas diffusion strategy to design dimension-controlled Fe-NC catalysts for the elimination of organic pollutants.(c) 2022 Elsevier Ltd. All rights reserved.