Design of Highly Stable and Efficient Bifunctional MX ene-Based Electrocatalysts for Oxygen Reduction and Evolution Reactions

Finding low-cost, highly active, and thermally stable bifunctional electrocatalysts toward oxygen reduction and evolution reactions (ORR-OER) is a key for the development of renewable energy devices, including fuel cells and water splitting. Here, we systematically investigate the physical properties, structural stability, and ORR-OER bifunctional catalytic activity of $\mathrm{Pt}$ supported by a series of MXene substrates using density-functional-theory calculations. Our results indicate that $\mathrm{Pt}$ atoms disperse uniformly on the MXene supports with high structural stability at high temperature and oxidation conditions, because of the strong metal-support interaction. The lattice parameter of MXenes is found to play a crucial role in determining the morphology and stability of these heterostructures and a descriptor is proposed for their design. In particular, $\mathrm{Pt}/{\mathrm{V}}_{2}\mathrm{C}$ is identified as the stable and most promising bifunctional catalyst with an overpotential comparable to the benchmarks. This work brings up a strategy for the search and design of superb transition metal/MXene catalysts for energy applications.