Two-dimensional (2D) transition metal carbides and nitrides (MXenes) have recently attracted considerable attention because of their electronic structure and properties that differ from their bulk counterparts. The general formula for MXenes is Mn+1XnTx where M is an early transition metal, X is carbon and/or nitrogen, T indicates various surface terminations, n= 1, 2 or 3, and x is the number of surface groups per unit formula. MXenes are produced by liquid exfoliation of MAX phases, the process results in selective removal of A layer elements (group 13 or 14 elements, i.e. Al) and formation of multilayered stacks of M-X 2D sheets. The unique properties exhibited by MXenes, such as good electronic, mechanical, and optical properties as well as their hydrophilicity, have remarkably driven the research and applications of MXenes for microelectronics sensors, water purification, energy storage, biosensors, hydrogen/oxygen evolution reactions etc. Amongst the reported MXenes, Ti3C2Tx has been studied the most to date. In this study, we report the thermal and chemical stability of V2CTx MXene under different atmospheres by combining in situ Raman spectroscopy with ex situ X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), and Scanning Electron Microscopy (SEM) in order to gain molecular-structural information from both the surface and bulk of these promising materials. We heated the material up to 600 °C under inert (N2), oxidative (CO2, air), and reductive (H2) environment with similar conditions. By combining ex situ and in situ studies, we demonstrate that the surface transforms differently as compared to the bulk structure as a function of temperature and environment. We aim to foster both V2CTx and MXenes in general as potential thermo-catalysts, beyond their already proved electro-catalytic applications.

Insights on the thermal and chemical stability of V2CTx MXene under different environments

2019 Spring National Meeting

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