the Ru nanorod for the VO(iii) vacancy formation, despite the distance of about 5 Å to the nearest Ru atom. We tentatively rationalize this charge transfer upon O-vacancy formation at the iii site by the direct contact between the Zr ion above the O-vacancy (4Zr) and the Ru atom 2a (distance 2.20 Å), which seems to promote the electron transfer and thus vacancy formation compared to the ZrO2 support (Figure ). In contrast, although the O-vacancy at the ii site is close to the 3Zr ion with a distance of 2.17 Å, the 3Zr ion does not interact directly with a neighboring Ru atom (1a), but via the uppermost lattice O atoms. Consequently, the lack of direct contact between the Ru atom 1a and the 3Zr ion (distance 2.86 Å) at the ii site results in almost no charge transfer. Thus, in specific cases charge transfer between the support and the Ru nanorod can also occur via direct contact between a Ru atom and a Zr ion neighboring an O-vacancy.