Two-Dimensional, Ordered, Double Transition Metals Carbides (MXenes)

The higher the chemical diversity and structural complexity of two-dimensional (2D) materials, the higher the likelihood they possess unique and useful properties. 2D materials offer high specific surface areas, as well as electronic structures and properties that differ from their bulk counterparts. In agreement with the disappearance of the MAX phase peaks in the X-ray diffraction (XRD) patterns after etching, energy dispersive X-ray spectroscopy confirmed a significant drop in the Al signals and concomitant increases in the F and O signals, implying that MXene surfaces are O, OH and F terminated. In summary, the authors predict that at 0 K, at least 26 ordered, double-M 2D carbides should be stable. Thus, numerous new structures with different transition metals in outer and inner layers and various surface terminations are possible, greatly expanding the family MXenes in particular and 2D materials in general.