Abstract: Layered double hydroxide (LDH) based heterogonous peroxymonosulfate (PMS) activation degradation of pollutants has attracted extensive attention. The challenge is to selectively regulate the traditional free radical dominant degradation pathway into a nonradical degradation pathway. Herein, an interface architecture of Ti₃C₂T_x-MXene (MXene) loading on the Fe-Al LDH scaffold was developed, which showed excellent stability and robust resistance against harsh conditions. Significantly, the rate constant for tetracycline hydrochloride (TC) degradation in the MXene-LDH/PMS process was 0.421 min^-1, which was ten times faster than the rate constant for pure Fe-Al LDH (0.042 min^-1). Specifically, more reactive Fe with the closer d-band center to the Fermi level results in higher electron transfer efficiency. The occupations of Fe-3d orbitals in Mxene/Fe-Al LDH are pushed above the Fermi level to generate, which results in higher PMS adsorption and inhibition of the release of oxygen-containing active species intermediates, leading to the enhanced ¹O₂ generation. Additionally, the built-in electric field in the heterojunction was driven by the charge redistribution between MXene and Fe-Al LDH, resulting in a mediated-electron transfer mechanism, differentiating it from the Fe-Al LDH/PMS system. It was fascinating that MXene/Fe-Al LDH achieved satisfactory treatment efficiency in continuous column reactor and real landfill leachate.

Key words: Interface engineering, Density functional theory, Layered double hydroxides, Peroxymonosulfate, Electron transfer