Hydrophobic MXene with enhanced electrical conductivity

Two-dimensional nanostructured (2D) layers of transition metal nitrides, carbides, or carbonitrides, known as MXenes, are inherently hydrophilic mainly due to the presence of surface terminating groups like –O, -OH, etc. In this work, hydrophilic MXenes have been converted to hydrophobic ones by low-energy N+ ion irradiation at different fluences. The removal of surface functional groups after irradiation is supported by various characterizations. DFT simulations confirm the strong influence of -OH and -O-OH on the hydrophilic nature of pristine MXene. Adsorption energy data reveals that the adsorption of water molecules on surface terminal group-free MXenes is energetically unfavorable, pointing towards hydrophobic character. Ion irradiation is exploited as a tool to partially remove the surface-terminating functional groups to make MXenes hydrophobic. Additionally, a remarkable enhancement in electrical conductivity has been noticed with increase in ion fluence, which can also be attributed to preferential sputtering of the functional groups and the structural change of MXene.