Atomic-Scale Interface for Pt Nanoparticles on SrTiO₃ (001)

The interfacial structure formed by Pt nanoparticles grown epitaxially on a SrTiO₃ (001) surface by pulsed laser deposition was studied by X-ray standing-wave (XSW) excited core-level photoelectron emission. The XSW-generated 3D atomic map of the Pt and interfacial oxygens for the oxidized Pt/SrTiO₃ interface differs significantly from that of the as-deposited interface. After oxidation, the Pt atoms shifted upward and their atomic occupation at fcc-like sites evolved as the oxidation temperature increased. Interfacial oxygen atoms were differentiated from bulk O atoms by the chemical shift in the binding energy of their 1s electrons. After oxidation, the interfacial oxygen atoms rearranged to form a TiO₂ bilayer at the interface. These results provide a more complete description of the strong metal-support interaction process at the interface.