Iron and nitrogen co-doped carbon catalysts derived from ZIF-8 towards enhanced peroxymonosulfate activation and contaminants removal: The synergistic effects of FeNx and α/γ-Fe species

The performance upgrading of iron and nitrogen co-doped carbon (Fe-N-C) for peroxymonosulfate (PMS) activation towards contaminants removal and elucidation of the activation mechanism still remains a challenge. In this study, novel iron and nitrogen co-doped carbon (Fe-N-C) catalysts are fabricated through pyrolysis of Fe-modified zeolitic imidazolate framework-8 (ZIF-8) nanocrystals. Catalytic experiments prove that synergistic effects of FeN_x and α/γ-Fe species can boost peroxymonosulfate activation and pollutants degradation. Density functional theory simulations disclose that α/γ-Fe species can optimize the d-band center of FeN_x and adsorption energy for PMS activation, and thus achieve the enhanced catalytic activities for degradation process. Mechanism studies testify that Fe-N-C-PMS* complex and ¹O₂ are main contributors for the catalytic process. This work paves a new way for elaborate design of high-performance Fe-N-C materials and understanding about the non-radical mechanism during environmental applications.