Anchoring single atom cobalt on two-dimensional MXene for activation of peroxymonosulfate

A simple and general vacancy defects anchoring strategy was developed for the synthesis of single atom metals, which exhibited excellent performance for peroxymonosulfate (PMS) activation. Production of Ti vacancy defects, conversion of metal ions to metal atoms, anchoring of single atom metals and construction of two-dimensional (2D) MXene structure on the eco-friendly Ti2AlN ceramic substrate were accomplished in one step using the molten transition metal salts. Complete removal of model pollutants including carbamazepine (CBZ), sulfamethoxazole (SMX) and 2,4-dichlomphen (2,4-DCP) was achieved within less than 2 min in PMS/ single atom Co process. Hydroxyl radical ((OH)-O-center dot), sulfate radical (SO4-(center dot)) and nonradical oxidation jointly contributed to pollutants degradation. More importantly, the exposed Ti atoms with strong reducibility of MXene substrate triggered the Co(III)/Co(II) cycle and thus accelerated PMS activation. The single atom Co catalyst exhibited excellent performance even under alkaline condition or in actual river water.