Dynamic electronic modulation of single-atom Fe sites with p-block metal coordination enables highly selective generation of FeIV = O in Fenton-like reactions

High-valent iron-oxo species (FeIV=O) have garnered increasing attention for water purification, while the selective generation of FeIV = O in Fenton-like reactions still lacks an effective control protocol at the atomic level. Here, we propose an innovative coordination strategy to develop a series of diatomic FeMp-N-C catalysts with p-block metals (Mp: Bi, In, and Sb) for improving the selectivity of FeIV = O generation via peroxymonosulfate (PMS) activation. The p-block metal coordination facilitates the chemical bonding with the terminal hydroxyl oxygen of PMS to construct an electron-rich microenvironment surrounding the Fe active center, thereby transferring twice as many electrons to enable FeIV = O production through the high-spin-state FeIII intermediates. Consequently, the steady-state concentrations of FeIV = O in FeMp-N-C/PMS systems are substantially enhanced by almost an order of magnitude compared to conventional Fe-N-C and state-of-the-art FeMd-N-C catalysts (Md: Cu, Mn, and Ni). Under p-block metal coordination, FeMp-N-C catalysts selectively shift the Fe-N-C-PMS* complex-mediated electron transfer regime into the FeIV = O-dominated oxidation process, ultimately accounting for the efficient and sustainable degradation of organic pollutants. Our findings demonstrate a fundamental breakthrough in atomic-level electronic engineering for the selective synthesis of FeIV = O, which will provide promising prospects for environmental remediation and other catalytic applications.