Fe-N-C Catalyst Derived from MOFs with Enhanced Catalytic Performance for Selective Oxidation of Emerging Contaminants

Abstract

Fe-N-C/peroxymonosulfate (PMS) systems have demonstrated selective oxidation of pollutants, but the underlying mechanism and reasons for variability remain unclear. In this work, we synthesized a highly active Fe-N-C catalyst derived from MOFs using a pyrolysis protection strategy. We assessed its catalytic activity by employing PMS as an activator for pollutant degradation. The presence of Fe-Nx sites favored the catalytic performance of FeMIL-N-C, exhibiting 23 times higher activity compared to N-C. Moreover, we investigated the degradation performance and mechanism of the FeMIL-N-C/PMS system through both experimental and theoretical analyses, focusing on pollutants with diverse electronic structures, namely bisphenol A (BPA) and atrazine (ATZ)N-C. Our findings revealed that the degradation of ATZ primarily follows the free radical pathway, whereas BPA degradation is dominated by electron transfer pathways. Specifically, pollutants with a low LUMO- HOMO energy gap (BPA) can be degraded via the FeMIL-N-C/PMS system through the electron transfer pathway. Conversely, pollutants with a high LUMO-HOMO energy gap (ATZ) exhibit limited electron donation and predominantly undergo degradation through the free radical pathway. This work introduces novel insights into the mechanisms underlying the selective oxidation of pollutants, facilitating a deeper understanding of effective pollutant removal strategies.