MXene, a two-dimensional transition metal carbide, nitride, or carbonitride, has received a tremendous amount of research attention since its discovery in 2011. The high specific surface area, hydrophilicity, conductivity and mechanical strength of MXenes make them promising for applications including energy storage, electromagnetic interference shielding, and catalysis . MXenes can be described as a hexagonal closed packed structure comprising of Mn+1XnTx (n=1 to 4; where M is early d block transition metal; X is carbon or nitrogen; T is surface terminated groups such as =O, -OH, -Cl, and -F, depending on the chemical etchant). Terminal group free MXenes (Mn+1XnT0) are determined to have D3d symmetry. However, the presence of the terminal groups distorts the symmetry of the unit cell. Hence, the literature generally refers to the unit cell of Mn+1XnT0 as pseudo-P63/mmc. MXenes are fabricated from corresponding MAX phases with the chemical composition of Mn+1AXn, where A is either group 3 or 4 elements (e.g., Al, Ga, Si) laying between the MXene layers. MXenes have very diverse chemical compositions due to the different combinations of M, A, and X elements. To date, more than 50 MXenes have been reported to be successfully synthesised. The family of MXenes is further expanded when two transition metals are mixed in a MXene structure, in which the transition metal may either be arranged randomly across all the M layers, or they may form ordered structures. Given that the ratio of M and X in these double transition metal MAX precursors can be controlled as needed, the number of possible MXenes can be limitless.