A C21Ge two-dimensional material with high sensitivity and strong adsorption capacity for CO

Density functional theory (DFT) calculations were employed to investigate the adsorption of a single CO molecule on C21Ge (named due to the presence of 21 carbon atoms and 1 germanium atom in its structure). The study involved the determination of the most stable geometric structures, adsorption energies, adsorption heights, and density of states for the system, exploring the interactions between the adsorbed CO molecule and the substrate. The results revealed a high degree of CO adsorption on C21Ge, with adsorption energies of −1.34 eV and −1.33 eV for C atoms near the adsorption site and O atoms near the adsorption site, respectively. The adsorption distances were determined to be 2.89 Å and 3.04 Å, with the most stable adsorption sites identified as H3 and B3. The adsorption strength was slightly higher when C atoms were in proximity compared to O atoms. The high degree of hybridization between the density of states orbitals indicated strong interactions between the CO molecule and C21Ge, emphasizing the pronounced adsorption capability of C21Ge for CO.