Two‐Dimensional Catalysts for Enhanced Hydrogen Storage in Magnesium Hydride: Materials, Mechanisms, and Future Perspectives

Abstract

Magnesium hydride (MgH 2 ) is a promising solid‐state hydrogen storage material due to its high gravimetric capacity and excellent reversibility. However, its practical application is hindered by high thermodynamic stability and sluggish reaction kinetics. Two‐dimensional catalysts, leveraging their unique advantages, such as atomic‐level thickness, ultra‐high specific surface area, abundant active sites, and tunable electronic structures, have emerged as an effective strategy to address these challenges. This review summarizes recent advances in two‐dimensional catalytic materials, including transition metal carbides, nitrides, or carbonitrides (MXenes), layered double hydroxides (LDHs), metal‐organic frameworks (MOFs), graphene derivatives, and metal nanosheets, as catalysts to modulate the hydrogen storage properties of MgH 2 . The underlying enhancement mechanisms can be categorized into three synergistic mechanisms: (1) physical: establishing rapid hydrogen diffusion pathways and nanoconfinement environments that stabilize nanoparticles and minimize diffusion distances; (2) electronic: modulating interfacial electron transfer through polarization effects to facilitate H 2 dissociation and Mg‐H bond destabilization; and (3) synergistic: exploiting multivalent cations and in situ formed active species during cycling to generate cooperative catalysis. In the end, future research directions are projected toward deciphering interfacial electronic redistribution and spatial effects in two‐dimensional catalysts, discerning universal catalytic mechanisms across material classes, and formulating predictive theoretical models and rational design strategies for next‐generation high‐performance magnesium‐based hydrogen storage systems, ultimately bridging the gap toward practical hydrogen storage applications.