Atomic Repartition in MXenes by Electron Probes

MXenes hold immense promise for diverse applications that highly depend on the compositional and structural features of both the carbide frame and interlayer functional groups. Here, we show that electron probes can controllably impart metal atoms in the carbide slabs to the functional group slabs in MXene multilayers. The multilayers consist of many few-atom-thick transition metal carbide slabs that are terminated with hydroxyl and O functional groups on each slab. Upon electron irradiation, the H atoms of the hydroxyl are knocked off, creating cation traps surrounded by dangling O confined in a nanosized slit. Simultaneously, the transition metal atoms partially struck away from the carbide slabs migrate into the cation traps periodically, resulting in atomic repartition. Atomic repartition is versatile for various MXenes and has the potential to improve the electric conductivity and lessen the anisotropy, providing a new method to synthesize new MXenes and holding significant implications in engineering MXenes at the atomic scale.