Gas adsorption and storage in metal-organic framework MOF-177

Gas adsorption experiments have been carried out on a zinc benzenetribenzoate metal-organic framework material, MOF-177. Hydrogen adsorption on MOF-177 at 298 K and 10 MPa gives an adsorption capacity of ∼0.62 wt%, which is among the highest hydrogen storage capacities reported in porous materials at ambient temperatures. The heats of adsorption for H ₂ on MOF-177 were -11.3 to -5.8 kJ/mol. By adding a H₂ dissociating catalyst and using our bridge building technique to build carbon bridges for hydrogen spillover, the hydrogen adsorption capacity in MOF-177 was enhanced by a factor of ∼2.5, to 1.5 wt% at 298 K and 10 MPa, and the adsorption was reversible. N₂ and O₂ adsorption measurements showed that O₂ was adsorbed more favorably than N ₂ on MOF-177 with a selectivity Of ∼ 1.8 at 1 atm and 298 K, which makes MOF- 177 a promising candidate for air separation. The isotherm was linear for O₂ while being concave for N₂. Water vapor adsorption studies indicated that MOF-177 adsorbed up to ∼10 wt% H ₂O at 298 K. The framework structure of MOF-177 was not stable upon H₂O adsorption, which decomposed after exposure to ambient air in 3 days. All the results suggested that MOF-177 could be a potentially promising material for gas separation and storage applications at ambient temperature (under dry conditions or with predrying).