A Density-Functional Theory of CO2 Interaction with a Hafnium-Titanium Nanocluster

Abstract

In this research, the formation of Hf_m-Ti_n nanocluster in six configurations of Hf_m-Ti_n and physicochemical behavior of CO₂ adsorption on Hf_m-Ti_n nanoclusters have been studied. The formation of the Hf-CO₂ and Ti-CO₂ bonds has been calculated using the DFT method. The effects of CO₂ adsorption on structural variations and electronic properties have been studied. The adsorption energy ΔE_ads, energy gap (E_g), HOMO and LUMO energies, and dipole moments have been calculated at the 6-311++G** basis set, considering the constant bond lengths of the adsorbed CO₂ molecules on Hf_n-Ti_5-n. The geometrical optimization has been performed by the B3PW91 method. The obtained results of adsorption values allow us to suggest that Hf doping on Ti nanocluster can noticeably improve the adsorption properties of all nanocluster models. Therefore, the decrease in global hardness and energy gaps after CO₂ adsorption on Hf_m-Ti_n nanoclusters can be attributed to the increase of chemical reactivity and hence leads to the lower stability of systems.