Adsorption of chemical species onto nanographenes, pristine coronene and anchored systems as coronene−(TiO2)n n=1–4: Insights from ab initio molecular dynamics calculations

Abstract

DFT (Density Functional Theory) calculations were carried out to evaluate the chemical interaction of CO (carbon monoxide) and NO (nitrogen monoxide) molecules onto nanographenes (NGs) n = 1–6 units; thus, for this range adsorption process is exhibited, excepting for n = 5 desorption is favored. On the other hand, dioxide titanium clusters (TiO2) n = 1–4 were proposed to adsorb CO molecule, atop and parallel adsorption sites were considered to attach CO molecule onto these clusters and four possible isolated models (C1-C4) are generated and as result of this chemical interaction, physisorption was obtained. In order to improve the adsorption of CO molecule, (TiO2)n−CO clusters are deposited onto (NG)2 to play the role as substrate, namely coronene (C) and then a set of nanocomposites are generated to analyze changes on adsorption tendency, for the above systems just CO molecule is considered. Some chemical and structural transition are obtained for largest sizes as well as adsorption energy values are more favored for C−(TiO2)3−CO system due to the close proximity between titanium atom of C-(TiO2)3 clusters and this chemical specie. Therefore, there are substantial chemisorption values in this instance due to the active sites. The values of the electronic gap do not exhibit significant variations, among these nanocomposites, however, the HOMO isosurfaces are shown in distinct ways, and for n ≤ 2 systems examined in this paper, LUMO isosurfaces are displayed at the center of the cluster. In all systems analyzed, the electronic transference goes from chemical species toward atoms at the adsorption site. These results suggest that these C−(TiO2)n nanocomposites are ideal candidates to storing or sense different sort of gases; thereby, these findings can be employed to design a kind of gases storage device for environmentally friendly energy applications.

Keywords

• DFT calculations
• Electronic and optic properties
• Clusters