These data also provide information on the effect of adsorbed CO on the energetics of Ovacancy formation, considering that this can be derived as the difference of the O-vacancy formation energy of a Ru/ZrO2 model system with an adsorbed CO and the COad-free Ru/ZrO2 model system. Such effects will be briefly discussed in section 3.2.4. Finally, we present an overview on the correlations between the CO adsorption energy on the one hand and the charge on the Ru adsorption site as well as the position of the d-band center on the other hand (section 3.2.5).