Coadsorption of CO and O on H-Capped (6, 0) Single-Walled Carbon Nanotube: A Density Functional Study

Abstract

The adsorption of oxygen atom, as well as the coadsorption of CO + O on (6, 0) carbon nanotube surface, was studied by using the density functional theory (DFT) method. Zigzag (6, 0) CNT was used to simulate the surface. The oxygen atom adsorbed on the site I of the CNT was the most favorable state. The coadsorption of O at the site I tended to block adsorption of CO at the different sites. Calculation indicated that CO may be absorbed on the O-CNT with the perpendicular adsorption configuration to the surface via C atom. The adsorption in the most favorable site occurred with the binding energy of −37.791 kcal·mol −1 . In this state, the calculated C-O stretch frequencies was read-shifted comparable with the calculated gas phase value, and the C-O distance was increased because of further electron transfers from O-CNT to anti-bonding orbital of CO. Too the reaction of CO + O → CO 2 on the (6, 0) CNT is predicted to be endothermic, and formed CO 2 species is not able to stably absorb on the surface.