Abstract
Effects of titania surface structure on the nucleation and growth of
Pt nanoclusters on rutile TiO2 (110)
We conducted a comparative study on the interaction of Pt with the (1x1) and (1x2) surface phases of rutile TiO2 (110) and found that the surface structure and stoichiometry of TiO2 have profound effects on the formation and growth of nano-sized Pt clusters. On the (1x1) surface, Pt formed randomly-distributed, three-dimensional nanoclusters that were subject to coalescence and encapsulation upon thermal annealing. In contrast, smaller Pt clusters were identified to adsorb on top of the titanium atomic rows on the (1x2) surface and exhibited higher thermal stability. The stronger interaction observed for Pt on the (1x2) surface is due to a charge transfer from Ti atoms to Pt atoms. To verify the different interactions of Pt with the two surfaces, we created a vicinal TiO2 (110) surface with alternating (1x1) and (1x2) domains. Upon Pt deposition, an array of self-organized Pt nanoclusters was formed on this surface. The self-organization is due to different interactions of Pt with the two different surface domains and preferential diffusion of Pt nanoclusters along the titanium atomic rows on the (1x2) surface.
