Ab initio study of metal-decorated carbon and silicon prismanes as the selective CO2 adsorbents.

In this paper, we conducted comprehensive analysis of the selective adsorption of CO₂ by carbon and silicon prismanes along with metal ions. The results of calculations from B3LYP/6-31G(d,p) and M06-2X/6-31G(d,p) levels of theory show that Be 2 + , Mg 2 + , Ca 2 + and Li + , Na + , K + ions are bounded strongly enough to prismanes. The Be 2 + ion binds more strongly to the C₈ H₈ cubane with binding energy 9.66 eV compared to Li + , Na + , K + , Mg 2 + and Ca 2 + ions having binding energies 1.26, 0.63, 0.51, 4.60 and 3.36 eV, respectively. Similar results were obtained for larger prismanes C 1 0 H 1 0 and C 1 2 H 1 2 . Instead of binding energy, we determine the adsorption of gases on metal-ion prismane complex along with effect of temperature on different gas adsorption shows that C₈H₈_Mg 2 + and C₈H₈_Be 2 + are active adsorbents at temperatures above room temperature. It is also observed that in comparison to N₂ and CH₄, CO₂ interacts more strongly with all prismanes decorated with metal ions. These non-covalent interaction plots are used to study the prismane and metal-ion interaction. Comparable study of silicon prismanes with M06 2X/6-31G (d, p) basis set, in terms of binding energy, adsorption of gases on prismane along with temperature effect, also possesses similar selectivity to CO₂ molecule with even higher adsorption energies. Thus, beryllium-decorated prismanes can be considered as promising adsorbents of carbon dioxide with good selectivity and high adsorption energy. [ABSTRACT FROM AUTHOR]