Hydrogen Storage in Metal-Organic Frameworks

Metal-organic frameworks (MOF) have versatile structures, high surface areas, and high pore volumes, and thus can be regarded as good materials for H 2 storage. The high H 2 capacities of MOFs at cryogenic temperatures dramatically decrease as the temperature increases to room temperature. Despite a relatively low isosteric heat of H 2 adsorption, the MOFs constructed from hexacarboxylic acid and with open copper sites have the highest excess H 2 uptake capacity at 77 K reported to date. Doping MOFs with catalysts is an effective approach to increase hydrogen storage capacities at ambient temperature because H 2 adsorption in MOFs promoted by metal-catalysts will take place by atomic hydrogen instead of molecular hydrogen, which will provide a high adsorption enthalpy much greater than 20 kJ mol -1.