Two-in-one strategy to enhance the stability of Ti3C2Tx in transition metal ion solutions.

Although MXenes have attracted significant attention across diverse fields, they exhibit a pronounced susceptibility to oxidation in aqueous environments, with oxidation significantly accelerated in the presence of transition metal ions (TMI) such as Fe3+ and Cu2+. This limitation impedes the synthesis of transition metal compounds/MXene-based composites and their potential for functional applications. In this study, we elucidate the mechanism of accelerated oxidation of Ti3C2Tx is that Fe3+ promotes the electron loss in Ti3C2Tx, thus leading to an increased production of hydroxyl radicals (OH) to oxidize Ti3C2Tx. Furthermore, a rational two-in-one strategy is provided with adding electron-rich ethylenediaminetetraacetic acid disodium zinc salt (ZnNa2EDTA) to enhance the stability of Ti3C2Tx by defect filling and electron donation. Consequently, the production of OH is significantly reduced and thus Ti3C2Tx remains well-preserved in the presence of Fe3+, which has also effectively enhanced the oxidation stability of Ti3C2Tx in the presence of Cu2+. This work is expected to pave a new pathway for targeted applications with coexisting Ti3C2Tx and TMI.