Modulating electronic structure of active sites on iron-based nanoparticles enhances peroxymonosulfate activation

Abstract

Herein, iron-based nanoparticle catalysts with heteroatoms anchored on nitrogen-doped carbon layers were constructed and applied to peroxymonosulfate (PMS) activation for antibiotic degradation. Results showed that S doping was beneficial to PMS activation, while P doping reduced the activation efficiency. The S-doped catalysts achieved 100% removal of sulfamethoxazole (SMX) within 15 min with a normalized rate constant of 130.4 min−1 M−1. Electron paramagnetic resonance and scavenging tests proved that high-valent iron-oxo species (HV-FeO) and singlet oxygen (1O2) mediated non-radical oxidation dominated the SMX degradation. Theoretical calculations and experiments elucidated that the electron-rich S atom donated electrons during PMS activation, which changed the valence state of Fe and enhanced the adsorption energy to PMS (Eads = −11.219 eV), resulting in excellent catalytic activity. This work elucidated the effects of heteroatoms on the electronic structure of active site in nanoparticles and provided guidance for the development of advanced catalysts for PMS activation.