Nanoconfined Single‐Atom Network With Tailored Mesoporous Pore Architecture for Stable Fenton‐Like Catalysis

Confining single metal atoms within nanoporous structure offers an effective strategy to improve their Fenton‐like catalytic activity and modulate the reaction pathway, but the underlying regulatory mechanisms remain elusive. Moreover, conventional single‐atom catalysts (SACs) with nitrogen‐doped carbon support generally suffer from high fabrication costs and limited long‐term stability. Herein, we fabricated a highly reactive and durable cobalt single‐atom network (Co‐SAN) by a facile hard‐template method and used it for efficient peroxymonosulfate (PMS) activation. The tailored mesoporous architecture of the Co‐SAN drastically strengthened the reactant enrichment relative to Co‐SAC and steered a catalytic pathway shift from singlet oxygen ( 1 O 2 ) to high‐valent Co (IV)═O species generation, rendering the catalytic system 50.5‐fold raised pollutant degradation kinetics. The nanoconfinement‐induced catalytic pathway shift was mainly caused by preferential formation of key O* intermediates at the convex interface. The Co‐SAN catalytic system exhibited robust decontamination performances across diverse environmental conditions and demonstrated high stability for continuous lake water purification in a flow‐through membrane reactor, highlighting its application potential for practical water purification.