Precise coordination of high-loading Fe single atoms with sulfur boosts selective generation of nonradicals.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38232287.
- Also identified by DOI 10.1073/pnas.2309102121 and PMC identifier 10823248.
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Abstract
Nonradicals are effective in selectively degrading electron-rich organic contaminants, which unfortunately suffer from unsatisfactory yield and uncontrollable composition due to the competitive generation of radicals. Herein, we precisely construct a local microenvironment of the carbon nitride-supported high-loading (~9 wt.%) Fe single-atom catalyst (Fe SAC) with sulfur via a facile supermolecular self-assembly strategy. Short-distance S coordination boosts the peroxymonosulfate (PMS) activation and selectively generates high-valent iron-oxo species (Fe<sup>IV</sup>=O) along with singlet oxygen (<sup>1</sup>O<sub>2</sub>), significantly increasing the <sup>1</sup>O<sub>2</sub> yield, PMS utilization, and <i>p</i>-chlorophenol reactivity by 6.0, 3.0, and 8.4 times, respectively. The composition of nonradicals is controllable by simply changing the S content. In contrast, long-distance S coordination generates both radicals and nonradicals, and could not promote reactivity. Experimental and theoretical analyses suggest that the short-distance S upshifts the <i>d</i>-band center of the Fe atom, i.e., being close to the Fermi level, which changes the binding mode between the Fe atom and O site of PMS to selectively generate <sup>1</sup>O<sub>2</sub> and Fe<sup>IV</sup>=O with a high yield. The short-distance S-coordinated Fe SAC exhibits excellent application potential in various water matrices. These findings can guide the rational design of robust SACs toward a selective and controllable generation of nonradicals with high yield and PMS utilization.