h -MBenes: Promising Two-Dimensional Material Family for Room-Temperature Antiferromagnetic and Hydrogen Evolution Reaction Applications.

Recently, a new class of two-dimensional (2D) hexagonal transition-metal borides ( h -MBenes) was discovered through a combination of ab initio predictions and experimental studies. These h -MBenes are derived from ternary hexagonal MAB ( h -MAB) phases and have demonstrated promising potential for practical applications. In this study, we conducted first-principles calculations on 15 h -MBenes and identified four antiferromagnetic metals and 11 electrocatalysts for the hydrogen evolution reaction (HER). Notably, the h -MnB material exhibited a remarkable Néel temperature of 340 K and a high magnetic anisotropy energy of 154 μeV/atom. Additionally, the hydrogen adsorption Gibbs free energies (Δ G H* ) for h -ZrBO, h -MoBO, and h -Nb 2 BO 2 are close to the ideal value of 0 eV, indicating their potential as electrochemical catalysts for HER. Further investigations revealed that the electronic structure, Néel temperature, and HER activity of the studied h -MBenes can be tuned by applying biaxial strains. These findings suggest that h -MBenes have wide-ranging applicability in areas such as antiferromagnetic spintronics, flexible electronic devices, and electrocatalysis, thereby expanding the potential applications of 2D transition-metal borides.