Interlayer Nanoconfinement Enhanced Peroxymonosulfate Activation for Nanozyme-Mediated Colorimetric Detection

The nonmonotonic dependence of nanoconfinement interlayer spacing on colorimetric-catalytic performance presents a critical challenge in the rational design of high-performance nanozymes. Herein, a nanoconfinement sensor (NCS) was developed by anchoring iron–cobalt layered double hydroxides (FeCo LDH) onto active carbon substrates, and the interfacial charge recombination-driven electron transfer mechanism within various nanoconfinement interlayers was decoded. The results reveal that a 0.94 nm nanoconfinement interlayer optimally enhances peroxymonosulfate (PMS) adsorption energy (Eads = −3.62 eV). The NCS-activated PMS system achieved ultrasensitive detection of 2-aminoresorcinol (2-ARS), with a limit of detection (LOD) of 0.17 μM, exhibiting a 2.6-fold improvement in activation efficiency compared to the NCS-activated hydrogen peroxide system. Theoretical calculations further identified three dominant interaction configurations, with parallel aromatic π–π stacking configurations exhibiting optimal adsorption energy (Eads = −0.39 eV) and thermodynamic stability. This was attributed to enhanced π-orbital alignment, which facilitated electron delocalization and interfacial charge transfer. Coupled with smartphone-assisted readout, the NCS system enabled real-time, high-precision 2-ARS monitoring in aqueous environments. This innovative approach offers a highly sensitive, user-friendly, and accessible platform for environmental detection and monitoring.