Effects of titania surface structure on the nucleation and growth of Pt nanoclusters on rutile TiO2(1 1 0)

A comparative study was conducted on the interaction of Pt with the (1×1) and (1×2) surface phases of rutile TiO2(1 1 0). It was found that the surface structure and stoichiometry of TiO2 have profound effects on the formation and growth of nanosized Pt clusters on TiO2(1 1 0). On the (1×1) surface, Pt formed randomly distributed, three-dimensional nanoclusters that coalesced and were encapsulated when thermally annealed. In contrast, smaller Pt clusters were identified to adsorb on top of the titanium atomic rows on the (1×2) surface and exhibited higher thermal stability. The stronger interaction observed for the Pt on the (1×2) surface is due to a charge transfer from Ti to Pt atoms. Vicinal TiO2(1 1 0) surfaces with alternating (1×1) and (1×2) domains were used to verify the different interactions of Pt for the two 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 (1×2) surface.