Low-dimensional materials for reversible hydrogen storage: A review of design principles, storage mechanisms, and emerging trends

Materials-based hydrogen storage is recognized for its high volumetric density, inherent safety, and seamless system integration, offering a practical route toward large-scale hydrogen deployment and deep decarbonization. Low-dimensional materials emerge as especially promising owing to their extensive surface area, tailorable chemistry, and short diffusion distances, which collectively enable high-capacity, reversible, and fast hydrogen storage. While extensive research has been devoted to specific materials, a cohesive understanding that interconnects findings across various material systems and yields transferable design principles remains lacking. This review develops an integrated mechanistic perspective spanning graphene derivatives, CN/BN/BCN frameworks, MXenes, transition-metal dichalcogenides, elemental monolayers, and emerging 2D architectures. The analysis covers polarization-enhanced physisorption, Kubas coordination, catalytic spillover, moderate chemisorption, and interlayer confinement, clarifying how structural motifs and chemical terminations govern adsorption energetics and reversibility. The most promising low-dimensional sorbents combine firmly anchored electropositive sites on graphene and nitrogen-rich frameworks, programmable terminations and galleries in MXenes that operate between physisorption and weak chemisorption, and composite architectures that enhance heat management and packing density. We further identify a shared near-ambient operating window and a set of device-aware metrics (working capacity, kinetics, cycling stability, and volumetric efficiency) as practical benchmarks to guide future synthesis, simulation, and prototype development.