An isosteric heat of adsorption (ΔHads) study was performed based on Clausius-Clayperon method, calculated from isotherms measured at both temperatures using the Sips model (see SI, Table , Figures S60-S61 and 6.a). The composites with a MOF contribution of up to 25% show stronger binding sites for CO2 at low coverages (ca 45 kJ/mol). With a larger amount of Ti-MOF, the enthalpy trend approximates to the values observed for the pure Ti-MOF at ca 30 kJ/mol. This indicates that the glass component provides strong polar sites that enhances the interactions with CO2 on its surface. This might also be related to the presence of the interface glass-MOF containing titanium phosphate at a local scale described in the section above. However, these data are not enough to confirm this synergic effect.