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 N(2), CO(2), and CH(4), 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.