Changes in activation pathways of the peroxymonosulfate system driven by nanoconfinement and active site regulation for efficient removal of organic micropollutants.

In this study, the nanoconfined channel catalysts (NCCX, X = 600, 700, 800, 900) with specific active centers were constructed to improve the electron transfer ability of the catalytic reaction and achieve peroxymonosulfate (PMS) activation pathway regulation. The confined catalytic system NCC700/PMS can achieve complete degradation of 2,4,6-trichlorophenol within 4 min, and its pseudo-first-order kinetic constant (1.33 min-1) is 2.38 times that of the non-confined system (0.56 min-1). Under the effect of the nanoconfined channel structure and active centers (Co-Nx) formed under high temperature conditions (≥700 °C), the generation path regulation of reactive oxygen species (ROS) was achieved, effectively promoting the generation of 1O2. Electrochemical tests and density functional theory (DFT) showed that the kinetic enhancement and ROS path transition were attributed to the nanoconfined effect, which promoted PMS adsorption and interfacial electron transfer at the active site and reduced the reaction energy barrier for 1O2 generation. The nanoconfined effect enhanced PMS adsorption and electron transfer, whereas active-site regulation modulates the ROS generation pathway and promotes 1O2 formation. This study not only provides new insights into the structural design of nanoconfined catalysts but also offers theoretical guidance for the application of nanoconfinement effects in advanced oxidation processes.