The thermal stability of ultra-thin Pt layers, deposited onto the TiO2(110)-(1xn) surface, was studied by scanning tunnelling microscopy at temperatures ranging from 300 to 1200K. As well as the formation of 3-dimensional particles and a gradual sintering of the initial clusters, one monolayer-deep vacancy-islands (pits) developed upon annealing at above 1000K. They appeared on the atomic terraces of substrates covered by a few percent of a monolayer of Pt. The edges of the pits were typically decorated with Pt nanoparticles, grown during annealing; thus showing that the bonding between the admetal and the substrate was strongest at these sites. The formation of the vacancy-islands was attributed to a decoration process, activated by heat treatment at above 500K. Depending upon the Pt coverage, 2 types of morphological state could be distinguished: At coverages of less than 5% of a monolayer, one pit contained one Pt nanoparticle. In the case of coverages greater than 15% of a monolayer, a few Pt nanoparticles were localized in a particular vacancy-island of round shape; typically at the perimeter of the pit.

Thermally Induced Formation of Vacancy-Islands on the Atomic Terraces of TiO2(110) Surface Covered by Pt. Berkó, A., Hakkel, O., Szökó, J., Solymosi, F.: Surface Science, 2002, 507-510, 643-8