1 Interdisciplinary Nanoscience Center - INANO-Fysik, iNANO-huset, Interdisciplinary Nanoscience Center, Science and Technology, Aarhus University2 Interdisciplinary Nanoscience Center, Faculty of Science, Aarhus University, Aarhus University3 Department of Physics and Astronomy, Science and Technology, Aarhus University4 Haldor Topsøe A/S5 Interdisciplinary Nanoscience Center - INANO-Fysik, iNANO-huset, Interdisciplinary Nanoscience Center, Science and Technology, Aarhus University6 Department of Physics and Astronomy, Science and Technology, Aarhus University
By means of scanning tunnelling microscopy (STM) the nucleation, growth and sintering of platinum nanoparticles (Pt NP's) was studied on vicinal and flat rutile titanium dioxide (TiO2) surfaces. Utilising physical vapour deposition, the nucleation of Pt NP's on TiO2 surfaces at room temperature (RT) was found to be random and invariant towards different surface morphologies and reduction states. Thus, the nucleation of Pt on TiO2 at RT is rather insensitive to the surface structure and surface defects. Vacuum-annealing at 600 K, 700 K and 800 K, respectively, led to lower densities of Pt NP's as a result of sintering. Sintering occurred at different rates at the TiO2 surfaces studied, indicating that the surface morphology and the amount of Ti3+ excess charge do have an influence on the particle stability. Observed changes in the NP distribution as a result of sintering can be explained inferring facile diffusion of Pt NP's along the  direction.
Physical Chemistry Chemical Physics, 2014, Vol 16, Issue 39, p. 21289-21299