STM characterization of size-selected V1, V2, VO, and VO2 clusters on a TiO2(110)-(1 × 1) surface at room temperature

► Vanadium monomers bind preferentially to upper threefold hollow sites on TiO2(110). ► Vanadium dimers are oriented along the bridging oxygen rows on TiO2(110). ► Evaporative deposition of vanadium results in a mixture of monomers and dimers. ► The vanadium atoms in VO and VO2 clusters bind to upper threefold hollow sites. ► VO2 clusters on TiO2 are longer along the [001] surface direction than VO clusters.