First principles study of carbon monoxide adsorption on zirconia-supported copper

We have calculated the adsorption energy of carbon monoxide on a monolayer of copper adsorbed on the (1 1 1) face of cubic zirconia. For the bulk oxide, we compute the structural parameters of cubic, tetragonal, and monoclinic ZrO2 and obtain good agreement with experimental parameters. We also analyze the structural relaxation of the stoichiometric, oxidized and reduced (1 1 1) surfaces of cubic zirconia (c-ZrO2). For adsorption of copper on stoichiometric c-ZrO2, we find that the preferred binding site is atop the terminal oxygen atom, favored by 0.4 eV over other high symmetry sites. Charge density rearrangement reveals that adsorption on the oxide support causes a depletion of charge from the Cu dz2 orbitals. Consequently, CO adsorption on zirconia-supported copper is significantly stronger than CO adsorption on clean c-ZrO2 or clean Cu(1 0 0).