Solvents dramatically influence the atomic composition and catalytic properties of Ti3C2Tx MXenes

A fast-growing family of two-dimensional materials, MXenes, has drawn much attention due to their excellent catalytic properties and wide range of applications. One of the most common ways to work with powder-based materials, such as Ti3C2Tx MXenes, consists in the dispersion of the catalytic materials in various solvents followed by drop-casting of the prepared suspensions onto desired surfaces. However, the solvent employed to prepare the powder dispersions can have noticeable effects on the electrochemical performance of the drop-cast samples. Herein, four different solvents (water, ethanol, isopropanol, and N,N '-dimethylformamide), used as dispersion media in the preparation of the Ti3C2Tx MXene samples, and their effects on the electrocatalytic activity of Ti3C2Tx MXenes towards the hydrogen evolution reaction (HER) were studied by linear sweep voltammetry. As shown in this work, the different solvents provoke changes in the roughness and dispersibility of the material, as well as a partial oxidation of the Ti3C2Tx microparticles which leads to dissimilar surface coverages, resulting in different overpotential values for the catalytic HER. The findings of this research are of crucial importance for knowledge about the electrocatalytic performance of MXene samples, and their storage and long-term usage.