RADICAL-BASED TunING THE SURFACE functionaliTY of MXene

Abstract

The family of MAX phases and their derivative MXenes are continuously growing in terms of both crystalline and composition varieties. MXenes are a new family of two-dimensional (2D) transition metal carbides, carbonitrides and nitrides, with a general formula Mn+1AXn, where n = 1-3, M denotes a transition metal, A is an element such as aluminum or silicon, and X is either carbon or nitrogen. Considering the various elemental composition possibilities, surface functional tunability, various magnetic orders, and large spin-orbit coupling, MXene can truly be considered as multifunctional materials that can be used to realize highly correlated phenomena. However, a change in surface chemical groups can significantly alter the properties and functionality of MXene flakes and may even damage the flakes. In this paper, we propose the possibility of using soft, chemical transformation to tune the MXene surface chemistry and termination. We used fluorinated and brominated substituents for MXenes grafting and subsequent analysis of the surface composition of the MXene flakes indicated a decrease in oxygen and a simultaneous increase in fluorine and bromine surface concentrations. The ability to graft organic groups with various substituents to the surface of the flakes opens up new possibilities for their application. The presence of fluorinated groups on the surface makes it hydrophobic, which allows the creation of water-repellent flakes, and prevents rapid oxidation by atmospheric oxygen and related formation of titanium oxide on the surface.