Nanoconfined active iron sites in porous silica trigger nonradical Fenton-like catalysis for efficient and sustainable water decontamination.

Heterogeneous Fenton-like catalysts hold great promise for water treatment, yet their practical applications are often constrained by insufficient activity and poor stability. Herein, a pore-confinement strategy is employed to immobilize highly dispersed iron species within hierarchically porous silica nanospheres (Fe-PSNs), enhancing peroxymonosulfate (PMS) activation for ultrafast water decontamination. The nanoconfined Fe-PSNs/PMS system achieved nearly complete removal of phenol within 3 min, with a rate constant of 2.0 min-1 that is 41.0 times higher than that of the nonconfined system. Mechanistic investigations reveal that the reaction proceeds predominantly via a nonradical pathway dominated by singlet oxygen generation. This endows the system with high selectivity for electron-rich pollutants and strong resistance to interference from complex water matrices. Furthermore, the Fe-PSNs catalyst maintains excellent robustness during real water treatment and successive reuse cycles. This work highlights the potential of nanoconfined strategies in heterogeneous Fenton-like catalysis and offers practical approaches for designing high-performance catalysts for sustainable environmental remediation.