In general, the d-band model relates the CO adsorption energy to the energy of the d-band center of the respective surface atom on the bare metal, in the absence of an adsorbate . Considering that adsorption can go along with a more or less pronounced restructuring of the metal, it would appear more plausible to use the d-band center of the restructured metal as reference. Therefore, we performed similar calculations for the Ru/ZrO2 systems with the structure frozen to that of the system carrying an adsorbed CO atom, but without the CO atom. This also means that the expected to be minor for adsorption on single-crystalline low-index metal surfaces, where adsorbate induced structural modifications are mostly small, while on structures like the present nanorod structures they may be more significant. The d-band centers resulting for the frozen structures of the Ru/ZrOx systems with a CO molecule on the top layer edge site or on the middle-layer site are compiled in Tables and, respectively. They exhibit slightly more pronounced, but still small changes, in the range of 0.1 eV, which is comparable to the trend in the CO adsorption energy. Hence, structural effects seem to be negligible in this case. For the systems frozen into the structure obtained for CO adsorbed on the interface (i) site, but with the COad removed, the resulting d-band center energies plotted as red line in Figure and listed in Table . These data show a similar trend upon O-vacancy formation as obtained for the original system (black line), but with the d-band center about 0.2 eV higher. Hence, the COad induced structural deformation leads to an enhanced ability to interact with CO (formation of the adsorption bond), while the trend for different O-vacancy locations does not change.