MAB phases have been gaining significant interest over the last 10 years due to their similarity to MAX phases. In both MAB and MAX phases M stands for a transition metal and A stands for a group 13 or 14 element; The X in MAX stands for carbon or nitrogen and the B in MAB is boron. MAX phases are three-dimensional crystals consisting of M-X layers interleaved with layers of A from which the A element can be removed to obtain two-dimensional M-X sheets called MXenes. It is predicted that, due to MAB phases having a similar layered character as MAX phases, a related process could occur with MAB phases to synthesize MBenes. The promise of a MBene is enticing as computational predictions suggest that MBenes would have desirable properties for applications such as catalysis and Li-ion batteries. Unfortunately, MAB phases do not withstand the harsh conditions under which MXenes are synthesized, leading us to take a milder approach to A-element removal. We have been able to take the stable MoAlB phase and manipulate it using various topochemical techniques to synthesize the metastable Mo2AlB2 phase by removing half of the Al atoms. Mo2AlB2 has been computationally predicted to be easier to exfoliate into a MBene than the parent MoAlB phase making it a phase worth further investigation. Leveraging different processes to synthesize Mo2AlB2 results in varying degrees of crystallinity which in turn impacts the products’ viability for use in the synthesis of a MBene. In comparing these products, we gain insight into what is required for MBene synthesis and how to begin removing Al while preserving the MoB layers.

Topochemical manipulations of MoAlB-derived compounds

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