A rising Layered Boride Family for Energy and Catalysis Applications: Novel Hexagonal MAB phases and MBenes.

Over the past decade, conventional MAX phases and MXenes have garnered significant interest, primarily limited to carbides and/or nitrides. However, in 2019, the hexagonal ternary boride Ti 2 InB 2 was successfully synthesized, sparking extensive research into hexagonal MAB (h-MAB) phases and their derived MBenes (h-MBenes). In recent years, h-MAB and h-MBenes have become focal points in the fields of physics, chemistry, and materials science. The unique properties and promising performances of h-MBenes in catalysis, energy storage, spintronics, and electrical devices underscore their considerable potential. Nonetheless, the exploration of h-MAB and h-MBenes is still in its nascent stages, with many anticipated properties and potentials yet to be fully explored. This article introduces the general concepts, crystal structure, and exfoliation properties of h-MAB phases, while also highlighting advancements in the synthesis and applications of h-MBenes. Finally, we discuss future challenges and prospects for the study of h-MAB and h-MBenes.