Hydrogen storage properties of Mg-based alloys modified with metal-organic frameworks and carbon-based porous materials: A review and summary

Solid-state hydrogen storage technology is currently the most economical, reliable, safe, and volumetrically efficient storage method. Unfortunately, whether physically or chemically adsorbed hydrogen storage, a single hydrogen storage material cannot be used as a medium for real-life applications. Among them, magnesium-based alloys have the highest mass density for storing hydrogen among metal-based alloys, while porous materials with physical adsorption properties have become a research hotspot for combining with metal hydrogen storage materials since they have the advantages of high specific surface area, low cost, abundant unsaturated active sites, exceptionally high porosity, adjustable pore size and structure, and tunability of composition. Hence, this paper intends to provide the readers with an overview and elucidation of the catalytic effects and mechanisms of metal-organic frameworks and carbon-based porous materials (activated carbon, carbon nanofibers, and carbon nanotubes) in improving the kinetic and thermodynamic properties of Mg/MgH2. The results demonstrated that MOFs and carbon-based porous materials act as catalysts, co-catalysts, inhibitors of grain agglomeration and sintering, and layered scaffolds in Mg/MgH2, respectively. The rational design of the Mg/MgH2 composite system was also prospected by comparing the advantages and disadvantages of these modification methods. To contribute a feasible idea and solution for the production of solid-state hydrogen storage materials with a high capacity for storing hydrogen, low cost, good hydrogen absorption/desorption kinetics, and excellent cycling stability for application in real industry and life.