Interestingly, the adsorption profile for Cu I Zn-MFU-4l above 5 bar at a given temperature appears almost parallel to the corresponding isotherm of ZnCl-MFU-4l. This observation prompted us to deconvolute the H2 uptake in Cu I Zn-MFU-4l into strong H2 binding at Cu I sites and weak physisorption at non-Cu I adsorption sites by fitting the adsorption isotherm data with a dual-site Langmuir equation. Gratifyingly, the H2 uptake can be modeled well by this approach, with the resulting fit parameters indicating the presence of a small number of strong adsorption sites and a larger number of weak adsorption sites. We generated two sets of simulated isotherms with these fitting parameters for strong and weak adsorption sites, assuming that these behave independently within the same material (Figure ). The profile of the simulated adsorption isotherm for the weak adsorption sites in Cu I Zn-MFU-4l resembles the H2 isotherm profile for ZnCl-MFU-4l within 10% difference, while the slight difference can arise from the difference in the pore size.