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Free keywords:
iron;
platinum;
supported catalysts;
surface analysis;
thin films
Abstract:
We studied the structure and thermal stability of Pt deposited on a Fe3O4(0 0 1) thin film to make a comparison with the Pt/Fe3O4(1 1 1) system that shows a strong metal–support interaction (SMSI) through encapsulation. Pt adatoms interact strongly with the (√2×√2)R45°-reconstructed Fe3O4(0 0 1) surface and adsorb monoatomically on the “narrow” sites. Metal sintering sets in only above 700 K to result in cuboid Pt nanoparticles exposing primarily (1 0 0) and (1 1 0) facets. Concomitantly, CO adsorption on Pt is fully suppressed as a result of the SMSI. The results provided strong evidence that the Pt nanoparticles on Fe3O4(0 0 1) are encapsulated by an FeO(1 1 1) layer in the same manner as observed for hemispherical Pt particles on Fe3O4(1 1 1). The comparison suggests that the SMSI effect through encapsulation is insensitive to the surface structure of the oxide, although the latter strongly affects the particle morphology.
