Two-step assembly induced Fe0-anchored graphitic N-rich graphene with biactive centers for enhanced heterogeneous peroxymonosulfate activation

Abstract

Herein, biactive centers of Fe⁰-anchored graphitic N-rich graphene (Fe-GNG) were constructed via coordination and hydrogen bonding assemblies followed by calcination. The obtained Fe-GNG exhibited excellent peroxymonosulfate (PMS) activation ability to degrade diverse organic pollutants, accompanied by very low activation energy. Electron paramagnetic resonance and quenching experiments indicated that ˙OH and ¹O₂ were the predominant reactive species responsible for organics degradation, and were generated from PMS activation mainly at Fe⁰ and graphitic N sites, respectively. The degradation process had wide pH (2.2–10.3) and temperature (5–45 °C) application ranges, and a high tolerance to common matrix species, which enabled application to natural water systems. Furthermore, the magnetic Fe-GNG catalyst exhibited high stability and reusability, still degrading over 90% organics after five runs. This work provides a feasible strategy to construct multiple active sites for PMS activation, and clarifies the synergistic effect of metal and carbonaceous materials in radical and nonradical activation processes.