Simple Approach to Enhance Long-Term Environmental Stability of MXene Using Initiated Chemical Vapor Deposition Surface Coating

Abstract

Developing a methodology to enhance long-term stabilityis oneof the most important issues in MXene research, since they are proneto oxidation in the ambient environment. Although various approacheshave been suggested to improve the stability of MXene, they have sufferedfrom complicated processes and limited applicability to various typesof MXene nanostructures. Herein, we report a simple and versatiletechnique to enhance the environmental stability of MXenes. Ti3C2T x MXene films weredecorated with a highly hydrophobic polymer, 1H,1H,2H,2H-perfluorodecylmethacrylate (PFDMA), using initiated chemical vapor deposition (iCVD)where iCVD allows the facile postdeposition of polymer films of desiredthickness on MXene films. The oxidation resistance was evaluated byfabricating MXene gas sensors and measuring the change in signal-to-noiseratio (SNR) of volatile organic compound (VOC) gases under harsh conditions(RH 100% at 50 degrees C) for several weeks where the performance inthe absence and presence of PFDMA was compared. The results show thatwhile the SNR of PFDMA-Ti3C2T x sensors was retained, a dramatic increase of the noise leveland a decrease in the SNR were observed in pristine Ti3C2T x . We believe that thissimple and nondestructive method will offer great potential to enhancethe stability of a wide range of MXenes.