Ar plasma modification of 2D MXene Ti 3 C 2 T x nanosheets for efficient capacitive desalination

MXenes are a new class of two-dimensional (2D) layered materials with excellent electrical conductivities, high specific surface areas and are overall environmentally benign. In terms of its structure, MXenes can be thought of as a stack of nanosheets with tunable interlayer spacings capable of rapid ion intercalation. As such, MXenes have been successfully employed as electrode materials in aqueous supercapacitors, Li-ion batteries and Na-ion hybrid supercapacitors in non-aqueous solutions. Herein, we report the novel application of MXenes Ti3C2Tx in a completely new field as capacitive water desalination. Interestingly, we found that the interlayer distance for the Mxenes Ti3C2Tx is able to be increased for efficient sodium ion transport by Ar plasma. To evaluate its desalination capabilities, the Ar plasma modified Ti3C2Tx was used as electrode materials and assembled in a capacitive deionization (CDI) cell. A high salt removal rate of 9.4 mg g−1 min−1 and an overall increased removal capacity of 26.8 mg g−1 was obtained when an external power of 1.2 V was applied. The desalination performance of Ar plasma modified Ti3C2Tx marks the foray of MXene materials in water desalination.