Chemically Tunable Ti₃C₂T MXene Surfaces

Modifying MXene surfaces is an effective strategy for controlling interactions with various chemical environments. Here, we demonstrate that treating Ti₃C₂T MXene surfaces with dilute acids and bases results in surfaces enriched with oxygen species capable of reversible proton exchange. These treatments produce surfaces with varying dispersibilities in different organic solvents that can be toggled between "on" and "off" states through successive treatments. Furthermore, we found that protonated MXenes exhibit slower ion kinetics due to surface passivation, whereas deprotonated MXenes show the opposite effect. This research opens avenues toward more versatile solution-based surface modification techniques that may rely less on specific MXene precursors and synthesis methods.