Fe N C single-atom peroxymonosulfate activator based on natural diatomite: Dispersion and strengthening mechanism

Iron single atom catalysts were supported on diatomite via Zif-8 precursor and atmosphere induction strategy. The introduction of diatomite makes it possible to regulate the pore structure and active sites of composite catalyst, and the ability of Fe-N-C/diatomite (Fe-N-C/DA) activated peroxymonosulfate (PMS) to degrade bisphenol A (BPA) was 11.8 times and 9.6 times that of pure catalyst and physical mixture. Furthermore, the carbon material forms a composite active center with iron single atoms and achieves efficient PMS activation. The density functional theory calculation results proved that the FeN4 center could grow oxygen-oxygen bond length to enhance PMS self-decomposition. Besides, tetravalent iron, superoxide radicals and singlet oxygen participate in the degradation process of BPA, and the possible degradation pathways of BPA in the Fe-N-C/DA/PMS system were also speculated. Our work provides a sight for the combination of natural minerals and monatomic catalysts to obtain an efficient, stable and potential persulfate activator.