Lamellar CoO@MXene/GO membrane switches non-radical pathway from electron transfer to singlet oxygen for ultrafast water decontamination

Spatial confinement switches non-radical pathways from ETP to a ¹O₂-dominant mechanism. • A 2D CoO@MX/GO membrane creates confined nanochannels for this transition. • Pathway shift confirmed by EPR, fluorescence, and DFT calculations. • Membrane achieves 10,000 × faster degradation kinetics than powder catalysts. • Size exclusion/confined oxidation resist NOM/ions for stable single-pass removal. Spatial confinement within a lamellar catalytic membrane is demonstrated to switch non-radical peroxymonosulfate activation from an electron-transfer process (ETP) to a singlet-oxygen ( 1 O 2 )-dominated pathway. This was achieved by intercalating cobalt oxide-decorated MXene nanosheets (CoO@MX) into graphene oxide (GO) laminates to construct a two-dimensional confined catalytic membrane. The membrane enabled four-orders-of-magnitude faster degradation of phenolic compounds than powder catalysts, with apparent rate constants of 0.093–0.127 ms –1 , achieved complete sulfamethoxazole removal within an ultrashort hydraulic residence time of 68 ms, retained approximately 95% removal under humic-acid interference, and maintained 100% removal efficiency over 50 h of continuous operation. The pathway transition toward singlet-oxygen-dominated oxidation, confirmed by electron paramagnetic resonance, in situ fluorescence, and density functional theory calculations, mitigates catalyst fouling and facilitates pollutant mineralization. This work provides a nanoconfinement strategy for steering non-radical oxidation pathways and offers a design principle for efficient, selective, and durable advanced oxidation systems for complex water treatment. Download: Download high-res image (181KB) Download: Download full-size image