| Abstract
| - The measurements and analysis of hydrogen adsorption isotherms on the metal−organic framework Zn4O(benzenedicarboxylate)3, IRMOF-1, at temperatures ranging from 50 to 100 K and pressures up to 40 bar are presented. The maximum excess adsorption amount measured on this material is about 9 wt % at 10 bar and 50 K. For the lowest temperatures, the measured excess adsorption isotherms exhibit a maxima and then decrease rapidly as function of pressure. The data collected in the decreasing region of the excess isotherms are used for the calculation of the adsorbed phase density and the absolute isotherms. Under these conditions, the adsorbed phase is found to behave like an incompressible fluid having a density comparable to that of hydrogen in its liquid state. The absolute isotherms, obtained by modeling the isotherms using a modified micropore filling model, can be up to 30% higher than the excess maxima depending on the equilibrium pressure and temperature. The adsorption enthalpy, expressed as function of fractional filling and temperature, lies within a typical physisorption range of 3−6 kJ/mol.
|
