This study is the analysis of the adsorption process of the CO2 molecule on the cationic sites of the DOH zeolite. Based on the DFT method, we have been able to identify several adsorption sites containing extra-framework cations and evaluate the value of the adsorption energy with respect to the distance from the adsorption site. The zinc cation has been found to cause the strongest interaction with the CO2 molecule. Subsequently, the adsorption process has been investigated by means of the Molecular Dynamics simulations. The results of the MD simulations are consistent with the geometry optimizations, and confirm the activation of CO2 molecule adsorbed in the Zn site.