New Methods of Functionalizing Organic Molecules onto 2D Ti₃C₂ MXene Surfaces

2D transition metal carbides, nitrides, and carbonitrides (MXenes) have unique and tunable physical, chemical, and mechanical properties that drive their application in chemical sensing, energy storage, and water purification. Among these properties, the excellent dispersion of Ti₃C₂ MXene in water remains one the most important for applications that require solution processibility. However, MXene susceptibility to oxidation in aqueous environments remains a challenge for suspension storage and environmental applications. While there are many computational works that predict property changes for MXenes with altered surface chemistry, successful and controlled experimental manipulation of MXene surfaces remains challenging. This work investigates new methods of controlled MXene surface functionalization that take advantage of the material’s intrinsic -OH and -O surface terminations. These methods are based on past group work involving the formation of organic molecular monolayers on metal oxides with hydroxylated surfaces. The organic molecules were bound to the metal oxide surface through alkoxy bonds, and the monolayers were found to be stable in aqueous environments. Current work utilizes X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy to elucidate the intrinsic and altered surface chemistry of lab synthesized 2D Ti₃C₂ MXene. This work is important for the development of a simple and controlled functionalization method for MXenes with the potential to bind a wide variety of molecules to the surface.