Finally, analysis of the different contributions to the total CO adsorption energy (𝐸 𝑎𝑑𝑠,𝑅𝑢/𝑍𝑟𝑂 2-𝑥 ) revealed distinct changes in the interface and deformation energies for adsorption on the interface (i) site when going from the 2VO to the 3VO system. These changes, however, seem to cancel each other, leading to an essentially constant CO adsorption energy.