Synthesis of Accordion-like Ti3CN MXene and its Structural Stability in Aqueous Solutions and Organic Solvents

Graphical The stability of accordion-like Ti 3 CN MXene in aqueous solutions, ethanol and N , N -dimethylformamide has been investigated. It is revealed Ti 3 CN exhibits limited stability in the aqueous solutions, and transforms to anatase TiO 2 nanoparticles in pH=1 and 7 solutions, and amorphous TiO 2 nanowires in pH=14 solution after a 7-day test at 25 °C. This transformation accelerates when the testing temperature increased to 80 °C. Meanwhile, Ti 3 CN shows excellent stability in ethanol and N , N -dimethylformamide after a 7-day test. MXene materials have shown promising applications in selective separation membranes and many other fields. However, their structural stability which is critically important to applications in the presence of aqueous solutions and organic solvents remains largely unexplored. In this work, we have conducted a systematic study on the synthesis of accordion-like Ti 3 CN MXene and its stability in aqueous solutions, ethanol and N , N -dimethylformamide (DMF). Based on the XRD, SEM and TEM results, 20 % HF acid and an etching time of 24 h is regarded as the optimal parameter to synthesize accordion-like Ti 3 CN MXene. Ti 3 CN MXene exhibits limited stability in the aqueous solutions. Ti 3 CN MXene partially transforms to anatase TiO 2 nanoparticles in pH=1 and 7 aqueous solutions, and amorphous TiO 2 nanowires in pH=14 aqueous solution after a 7-day test at 25 °C. When the testing temperature is increased to 80 °C, this structure transformation rate is increased remarkably. Meanwhile, Ti 3 CN MXene shows excellent stability in C 2 H 5 OH and DMF up to 7-day at 25 and 80 °C, respectively. It is believed that these findings are helpful for guiding the controllable synthesis of Ti 3 CN MXene and seeking the potential applications in the presence of aqueous solutions, ethanol and DMF.