Atomically Dispersed Fe-Mo Catalysts Mediate Fenton-Like Reaction to Efficiently Degrade Chlorophenol Pollutants Through Synergistic Oxidation and Dechlorination Reactions.

Chlorophenols are difficult to degrade and mineralize by traditional advanced oxidation processes due to the strong electronegativity of chlorine. Here, a dual-site atomically dispersed catalyst (FeMoNC) is reported, which Fe/Mo supported on mesoporous nitrogen-doped carbon is prepared through high-temperature migration. The FeMoNC exhibits a high dechlorination rate of 93.3% within 1 min. Theoretical calculation suggested that the doping of high-valence Mo as the electron reservoir, promoted electronic delocalization at Fe sites, thereby enhancing the adsorption and dissociation of peroxymonosulfate (PMS), subsequent generation of Fe (IV) = O and singlet oxygen (O) species. An interesting finding is that Mo sites can adsorb chlorine sites in 4-chlorophenol (4-CP) and induce C─Cl bond fracture. Thus, the FeMoNC/PMS system has high catalytic performance due to the synergistic effects of Mo-induced dechlorination and non-radical species (Fe(IV) = O and O) as the degradation pathways, the degradation efficiency of 99.1% of 4-CP within 5 min without significant performance decline after 168 h ≈15,120-bed volumes. These findings can advance mechanistic understanding of PMS activation at the molecular level and guide the rational design of efficient eco-friendly single-atom catalysts (SACs) catalysts with bimetallic atomic sites.