Unlocking the Catalytic Potential of 2D Metal Membranes for Hydrogen Evolution

Due to their inherent large reactive surface area and high electrical conductivity, two-dimensional (2D) materials have been extensively studied as candidates for hydrogen evolution reaction catalysts, often requiring doping or defects to enable catalytic activity. In this study, we systematically investigated the fundamental properties and hydrogen adsorption behaviors of various 2D metal membranes, using first-principles calculations to understand their potential as catalysts for hydrogen evolution. We discovered that, owing to the abundant surface states near the Fermi level, 2D metal membranes exhibit notably higher reactivity toward hydrogen and other molecules' adsorption compared to typical 2D materials. Among the 47 elements considered, seven demonstrate outstanding intrinsic catalytic activities without requiring doping or defect engineering, with potassium, magnesium, and copper membranes emerging as optimal materials in terms of catalytic activity. We further propose an encapsulation strategy using graphene layers to effectively shield these 2D membranes from undesirable molecular adsorption and chemical reactions that may compete with hydrogen evolution reactions. Such encapsulated membranes still preserve their catalytic activities for hydrogen adsorption and are also well-suited for the Volmer–Tafel-type mechanism, especially in an acidic electrolyte. These findings have significant implications for future applications of 2D metal membranes in catalysis, urging further exploration of these novel 2D materials.