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

Abstract

High-valent iron-oxo species (Fe^IV=O) have garnered increasing attention for water purification, while the selective generation of Fe^IV = 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 FeM_p-N-C catalysts with p-block metals (M_p: Bi, In, and Sb) for improving the selectivity of Fe^IV = 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 Fe^IV = O production through the high-spin-state Fe^III intermediates. Consequently, the steady-state concentrations of Fe^IV = O in FeM_p-N-C/PMS systems are substantially enhanced by almost an order of magnitude compared to conventional Fe-N-C and state-of-the-art FeM_d-N-C catalysts (M_d: Cu, Mn, and Ni). Under p-block metal coordination, FeM_p-N-C catalysts selectively shift the Fe-N-C-PMS^* complex-mediated electron transfer regime into the Fe^IV = 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 Fe^IV = O, which will provide promising prospects for environmental remediation and other catalytic applications.