Native Vacancy Defects in MXenes at Etching Conditions

Two-dimensional MXenes have recently received increased attention due to their facile synthesis process and extraordinary properties suitable for many different applications. During the wet etching of MXenes, native defects, such as metal carbon or nitrogen vacancies, are produced, but underlying defect formation processes poorly understood. Here, we employ first-principles calculations evaluate energies Ti, C, N vacancies in Ti3C2 Ti2N under conditions. We carefully account mixed functionalization surfaces well chemical environment solution (pH electrode potential). observe that differ significantly types surface local global environments. attribute these differences electrostatic interactions between surrounding functional groups. predict Ti will be prevalent on bare OH-functionalized not O-functionalized ones. In contrast, C more surfaces. addition, our results suggest pH value potential strongly affect vacancy formation. particular, predicted conditions at which abundant is expected compared experiments found coincide with oxidize readily. This suggests a crucial step initiating oxidation process.