The effect of the interlayer element on the exfoliation of layered Mo₂AC (A = Al, Si, P, Ga, Ge, As or In) MAX phases into two-dimensional Mo₂C nanosheets

Abstract

The experimental exfoliation of layered, ternary transition-metal carbide and nitride compounds, known as MAX phases, into two-dimensional (2D) nanosheets, is a great development in the synthesis of novel low-dimensional inorganic systems. Among the MAX phases, Mo-containing ones might be considered as the source for obtaining Mo₂C nanosheets with potentially unique properties, if they could be exfoliated. Here, by using a set of first-principles calculations, we discuss the effect of the interlayer 'A' element on the exfoliation of Mo₂AC (A = Al, Si, P, Ga, Ge, As or In) MAX phases into the 2D Mo₂C nanosheets. Based on the calculated exfoliation energies and the elastic constants, we propose that Mo₂InC with the lowest exfoliation energy and the highest elastic constant anisotropy between <i>C</i>₁₁ and <i>C</i>₃₃ might be a suitable compound for exfoliation into 2D Mo₂C nanosheets.