Recently, Fe single-atom catalysts activating peroxymonosulfate (PMS) have been of great potential to degrade recalcitrant organic pollutants. However, the mechanism of the unfavorable metal agglomerates produced throughout high-temperature pyrolysis on the Fenton-like reaction still remains confused. Herein, an efficient and stable catalyst integrating Fe single atoms with ultrafine atomic clusters (Fe_UAC@Fe_SA-NC) was successfully synthesized. The Fe_UAC@Fe_SA-NC/PMS system exhibited nearly 100% sulfamethoxazole (SMX) decomposition performance over a broad range of pH 3.0-9.0. Considering the difference in SMX degradation rate with or without Fe ultrafine atomic clusters, the catalytic performance of leached Fe ions, and the permissible Fe leaching concentration, it was not necessary to acid leach the Fe_UAC@Fe_SA-NC catalyst before use. Density functional theory (DFT) calculations manifested that the isolated Fe single-atom site neighbored by ultrafine atomic clusters acted as the optimal active site for PMS activation, and simultaneously the pyrrolic N served as the SMX adsorption site. The reactive species, including ¹O₂, ·O₂^-, SO₄^-· and ·OH radicals and activated metal-peroxo species (Fe-PMS*), played the key role in Fe_UAC@Fe_SA-NC/PMS system. The satisfactory SMX removal efficiency and mineralization rate in actual wastewater imply that this efficient heterogeneous catalytic PMS system is a promising approach for sustainable wastewater reclamation applications.

最近，Fe单原子催化剂活化过一硫酸盐（PMS）在降解难降解有机污染物方面具有巨大潜力。然而，类芬顿反应在高温热解过程中产生的不利金属团聚体的机理仍不清楚。在此，成功合成了一种高效稳定的将 Fe 单原子与超细原子团簇结合在一起的催化剂（Fe _UAC @Fe _{SA -NC）。}Fe _UAC @Fe _SA-NC/PMS 系统在 pH 3.0-9.0 的广泛范围内表现出近 100% 的磺胺甲恶唑 (SMX) 分解性能。考虑到有无 Fe 超细原子团簇的 SMX 降解速率、浸出的 Fe 离子的催化性能以及允许的 Fe 浸出浓度的差异，Fe _UAC @Fe _SA -NC 催化剂在使用前无需酸浸。密度泛函理论 (DFT) 计算表明，与超细原子团相邻的孤立 Fe 单原子位点是 PMS 活化的最佳活性位点，同时吡咯 N 作为 SMX 吸附位点。活性物质，包括¹ O ₂、·O ₂ ^-、SO ₄^- · 和 ·OH 自由基和活化的金属过氧化物 (Fe-PMS*) 在 Fe _UAC @Fe _SA -NC/PMS 系统中起关键作用。在实际废水中令人满意的 SMX 去除效率和矿化率意味着这种高效的多相催化 PMS 系统是可持续废水回收应用的一种有前途的方法。