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

Abstract

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[Formula: see text], Mg[Formula: see text], Ca[Formula: see text] and Li[Formula: see text], Na[Formula: see text], K[Formula: see text] ions are bounded strongly enough to prismanes. The Be[Formula: see text] ion binds more strongly to the C8 H8 cubane with binding energy 9.66[Formula: see text]eV compared to Li[Formula: see text], Na[Formula: see text], K[Formula: see text], Mg[Formula: see text] and Ca[Formula: see text] ions having binding energies 1.26, 0.63, 0.51, 4.60 and 3.36[Formula: see text]eV, respectively. Similar results were obtained for larger prismanes C[Formula: see text]H[Formula: see text] and C[Formula: see text]H[Formula: see text]. 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[Formula: see text] and C8H8_Be[Formula: see text] 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.