Several mechanisms have been reported for gas adsorption, including the gate-opening mechanism , the flip motion of the linkers , and the linker swing motion . The low-temperature heat capacity measurements of ZIF-8 confirm the structural change of the framework upon adsorption . Data analysis revealed CO2 rearrangement and lattice expansion . The adsorption mechanism depends on several parameters, including temperature . A study reported no gate opening related in the temperature range of 133 K and 227 K . There are three sites for the binding of CO2 and ZIF-68 (at 298 K and 1 kPa); the center of the HPR cages (Site I), the corners of the GME cages (Site III), and the nearby bIM linkers of the KNO cages (Site III), as shown in Figure 10 . Another study was reported using the van der Waals density functional model to study the binding of CO2 into ZIFs materials . The data analysis reveals the presence of three distinct binding sites for CO2 . with permission from Ref. . Copyright belongs to Elsevier.