Controllable Supply–Demand Effect during Superior Fe Single-Atom Catalyst Synthesis for Targeted Guanine Oxidation of Antibiotic Resistance Genes

Nonradical Fenton-like catalysis offers an opportunity to degrade extracellular antibiotic resistance genes (eARGs). However, high-loading single-atom catalysts (SACs) with controllable configurations are urgently required to selectively generate high-yield nonradicals. Herein, we constructed high-loading Fe SACs (5.4-34.2 wt %) with uniform Fe-N₄ sites via an optimized coordination balance of supermolecular assembly for peroxymonosulfate activation. The selectivity of singlet oxygen (¹O₂) generation and its contribution to eARGs degradation were both >98%. This targeting strategy of oxidizing guanines with low ionization potentials by ¹O₂ allowed 7 log eARGs degradation within 10 min and eliminated their transformation within 2 min, outperforming most reported advanced oxidation processes. Relevant interactions between ¹O₂ and guanines were revealed at a single-molecule resolution. The high-loading Fe SACs exhibited excellent universality and stability for different eARGs and water matrices. These findings provide a promising route for constructing high-loading SACs for efficient and selective Fenton-like water treatment.