Henry's law constant characterizes the slope of the linear part of adsorption isotherms. In Figures 7 (a) and (b), large-pore MOFs exhibit a higher average Henry's law constant, resulting in a greater isotherm slope at low loading regimes compared to small-pore MOFs, consistent with the trend observed in Figures ) and (h). Figure (c) shows the Henry's selectivity distribution for the two types of MOFs. Both distributions have peaks around a value of 10 3 . However, small-pore MOFs are able to reach significantly higher selectivity values (> 10 6 ). For small-pore MOFs, nitrogen can be completely rejected, leading to zero uptake and selectivity approaching infinity. While the size exclusion effect seems to be a plausible explanation for the behavior of smallpore MOFs, the origins of the high-selectivity trends in the larger-pore MOFs are less intuitive and hence we want to shed some light on this behavior. For this, we analyze the interaction energy between gas molecules and framework atoms at adsorption equilibrium. Table outlines the top 4 framework atoms that contribute to this interaction energy for CO2 molecules across various largepore MOFs. From Table , it becomes evident that in these MOFs, CO2 molecules are predominantly attracted to the oxygen atoms of the node building blocks. This effect is further illustrated in Figure , which shows molecular visualizations of two large-pore MOFs (Figures 9