Titanium-decorated graphene oxide for carbon monoxide capture and separation

Abstract

We propose titanium-decorated graphene oxide (Ti–GO) as an ideal sorbent for carbon monoxide (CO) capture and separation from gas mixtures. Based on first-principles calculations, Ti–GO exhibits a large binding energy of ∼70 kJ mol⁻¹ for CO molecules, while the binding energies for other gases, such as N₂, CO₂, and CH₄, are significantly smaller. The gas adsorption properties of Ti–GO are independent of the local GO structures once Ti atoms are anchored by the oxygen-containing groups on the GO surface. The strong interaction between CO molecule and Ti is a result of dative bonding, i.e., hybridization between an empty d orbital of Ti and an occupied p orbital of CO. Adsorption isotherms from grand canonical Monte Carlo simulations clearly demonstrate the strong selectivity of Ti–GO for CO adsorption in a mixture with other gas.