Single-atom copper embedded in two-dimensional MXene toward peroxymonosulfate activation to generate singlet oxygen with nearly 100% selectivity for enhanced Fenton-like reactions

Abstract

Singlet oxygen (1O2)-dominated advanced oxidation processes has drawn widespread attention for selective oxidation of organic pollutants in complex water environments. However, the high efficiency and selectivity of 1O2 generation remains challenging. Herein, we develop single-atom copper anchored on Ti3C2Tx MXene nanosheets (Cu-SA/MXene) by molten salt etching for the generation of 1O2 via peroxymonosulfate (PMS) activation. Particularly, it exhibits a high selectivity of 99.71% toward 1O2 generation by activating PMS, which shows outstanding catalytic activity for multiple pollutants, and strong resistance to inorganic anions. Experimental and theoretical results reveal that the Cu single atoms with three oxygen coordination environments (Cu-O3) are more favorable for PMS absorption and selectively adsorb the terminal oxygen of PMS to promote the generation of SO5.-, resulting in the generation of 1O2. A continuous-flow wastewater system by dispersing catalysts on poly (vinylidene fluoride) membrane exhibit stable catalytic activity for polycarbonate plant wastewater treatment over 8 h.