First-principles study of the adsorption of CO on TiO2(110) -: art. no. 045419

The adsorption of CO on TiO2(110) is investigated using the full-potential linearized-augmented-plane-wave method. The equilibrium structures of the clean and adsorbed TiO2(110) surfaces are optimized through total-energy and atomic force calculations. Two geometries of CO absorption, namely, OC-Ti and CO-Ti, were considered. It is found that the former orientation is preferred. The calculated adsorption energy and redshift of the CO stretch frequency based on the local-density approximation are 0.79 eV/molecule and 23 cm(-1) respectively. The gradient corrections reduce the CO-TiO2 binding energy to 0.25 eV/molecule. CO interacts with the TiO2(110) substrate mainly via its 5 sigma state. Significant charge redistribution is involved in the CO/TiO2(110) interaction, which changes the Coulomb potential and subsequently causes large shifts in the core and valence states of the CO adsorbate.