Synthesis Science between MAX phases and MXenes

The synthesis of MAX phases and their two-dimensional siblings MXenes, especially when pushing beyond Ti-based compounds, is far from trivial. Our group uses diverse preparation techniques to access new versions of these intriguing types of materials, recent examples include Cr₂GaC in the shape of carbonaceous microwires,¹ hollow and full microspheres² as well as hitherto unknown carbonitride phases, such as Cr₂GaC_1-xN_x and V₂GaC_1-xN_x.³ We specialize in non-conventional methods, such as sol-gel chemistry^4–6 and microwave heating⁷ to synthesize the MAX phases.
In this talk, I will highlight two of our recent projects: (i) Our work on a unique “514” MAX phase (Mo_0.75V_0.25)₅AlC₄, its structural investigation and transition to the respective MXene including its electrocatalytic properties. (ii) The transition from a MAX-like “221” compound Mo₂Ga₂C to the fully exfoliated MXene Mo₂CT_x as well as Mn-doped variants. All materials are structurally characterized by diffraction and microscopy techniques and a deeper understanding of their chemical composition, formation mechanism and stability is obtained through spectroscopy and thermogravimetric methods.