Role of metal-organic framework in hydrogen gas storage: A critical review

Hydrogen gas, well-known for its remarkable energy density (0.0107 MJ/m³ at STP), is gaining recognition as a potential substitute fuel due to its positive environmental impact. However, the significant hurdle of secure and effective storage of H2 continues to be a pressing issue. Investigating this challenge, we delve into the potential of metal-organic frameworks (MOFs) as a compelling solution, subjecting them to a thorough analysis. We begin by underscoring the significance of H2 as an energy carrier, necessitating effective storage. We explore H2 adsorption on MOFs, highlighting their unique properties and potential for enhanced storage capacity. This review encompasses MOF structure, synthesis, and characterization techniques. It probes MOF-based on carboxylates, nanocomposites, and metal cluster-building components, emphasizing tunable properties and performance in H2 storage. Design strategies involving supramolecular Building Layers and MOF Pillaring Design are explored, showcasing their ability to enhance H2 adsorption properties. Additionally, we highlight fluorine-containing and carbon-based MOFs, renowned for their remarkable H2 storage capabilities, achieved through tailored structures and expansive surface areas. This review explores the application of activated carbon derived from nanoporous polymers for hydrogen adsorption, emphasizing the crucial involvement of carbon-based materials in physisorption methods. To enhance the comprehension of MOFs, we integrate calculations using Density Functional Theory (DFT), Molecular Dynamics simulations, and Grand Canonical Monte Carlo (GCMC) simulations. This all-encompassing examination serves as a valuable reference for scientists and engineers, delivering profound insights and notable progress in the field of MOFs for hydrogen gas storage. Despite tremendous advancements in the field of MOF-based hydrogen storage, a significant gap remains for practical applications due to safety concerns. Further, storing H2 at 77 K is not very practical due to the requirement of liquid nitrogen. The preferred storage condition would be at 10–100 bar and near room temperature (298 K). Nevertheless, some outstanding results obtained with she-MOF-1 demonstrate exceptional H2 adsorption with a high storage capacity of 12.60 wt % at temperature 77 K and pressure 100 bars, making it promising for applications requiring substantial H2 storage. Additionally, MOF-5's remarkable BET (Brunauer-Emmett-Teller) surface area of 3512 m2/g positions it advantageously in adsorption-driven processes. Analysing H2 adsorption properties of fluorinated (Co-FINA-1 and Co-FINA-2) and non-fluorinated (Co-INA-1 and Co-INA-2) MOFs reveals that fluorination significantly increases H2 storage capacities, with Co-FINA-1 exhibiting the highest storage at 1.97 wt % at 77 K and 1 bar pressure, highlighting the positive impact of fluorination on H2 adsorption. The review highlights promising materials for hydrogen storage, such as she-MOF-1 with exceptional 12.60 wt % adsorption, MOF-5's remarkable BET surface area and the positive impact of fluorination on storage capacities, underscoring their potential for sustainable and economically viable H2 storage systems.