Monitoring Interface Interactions by XPS at Nanometric Tin Oxides Supported on Al2O3 and Sb2Ox

Two model systems consisting of nanometric SnO and SnO2 particles deposited by evaporation on Al2O3 and Sb2O3 or Sb2Ox substrates (x means a mixture of Sb3+ and Sb5+ oxidation states) are studied by X-ray photoelectron spectroscopy to account for the interactions that develop at the interfaces. The conclusions derived from this study are relevant for the characterization by this technique of nanostructured materials formed by nanoparticles and/or very thin films of an oxide deposited on another oxide support. Electronic parameters such as the binding energy (BE) of the Sn 3d5/2 photoemission peak and the Auger parameter (α‘) of the metal cation of the deposited tin oxides shift systematically from a nanometric size of the deposited moieties to a thick layer of these materials. The changes in the electronic parameters between the thickest layers of the deposited oxides and the first deposition situations (i.e., ΔBE, Δα‘, both in eV) are as follows for the different systems:  SnO/Al2O3 (ΔBE = 1.0, Δα‘ = −1....