Formation of hydrocarbons and carbon oxides in MXene reactions with water under varying oxidative conditions.

Titanium carbide/carbonitride MXenes have garnered significant attention due to their remarkable properties, versatile solution processability, and broad range of potential applications. However, when exposed to the environment, MXenes are susceptible to degradation, which ultimately leads to the formation of metal oxides, a process that may be regarded as either disadvantageous or beneficial, depending on the application of a MXene and our knowledge about the underlying mechanisms. Therefore, it is very important to understand the reactivity of MXenes in different environments and conditions. Although researchers have made efforts to understand MXene degradation in air and water, our knowledge of the involved processes and even products of degradation remains incomplete. Here, we study the degradation of MXenes (Ti2CTx, Ti3C2Tx, and Ti3CNTx) under various oxidative conditions, in the presence of hydrogen peroxide, oxygen, ambient air, and argon. Gaseous products of MXene degradation in an aqueous environment were examined using gas chromatography (GC) equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID) working in series. In addition to methane and carbon dioxide, gaseous products including higher hydrocarbons were identified and analyzed. This research further deepens our understanding of the fundamental chemistry of MXenes.