The evolution of a Fe/z'-TiOx/Pt(111) model catalyst in ultrahigh vacuum, studied by advanced surface science tools, reveals various phenomena occurring in different temperature ranges. In the room temperature (RT) < T < 460 K range, the deposited Fe atoms assemble as heterogeneous Fe and FeOx nanoparticles (NPs), templated by the ordered array of defects (troughs and picoholes) of the oxide film. At 460 < T < 810 K, FeOx NPs become predominant, and a metastable FeOx/TiOx mixed oxide is formed, assisted by the interdiffusion of Fe through the oxide into the Pt substrate, which triggers the z'-TiOx structure transformation into a different TiOx phase with a hexagonal pattern. At 810 < T < 1000 K, a Fe-mediated extraction of Pt produces Pt(111) islands, surrounded and partly encapsulated by the same z'-TiOx phase, demonstrating the intrinsic high stability of the ultrathin oxide film. This represents one of the first examples of a phase transformation in a ultrathin oxide layer induced by an external metal deposit.

Artiglia, L., Cavaliere, E., Rizzi, G., Gavioli, L., Granozzi, G., Probing Transformations of Relevance in Catalysis on a Single Oxide Layer: Fe on TiOx/Pt(111), <<THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS>>, 2010; 2010 (1): 1660-1665. [doi:10.1021/jz100511s] [http://hdl.handle.net/10807/6150]

Probing Transformations of Relevance in Catalysis on a Single Oxide Layer: Fe on TiOx/Pt(111)

Artiglia, Luca;Cavaliere, Emanuele;Gavioli, Luca;Granozzi, Gaetano
2010

Abstract

The evolution of a Fe/z'-TiOx/Pt(111) model catalyst in ultrahigh vacuum, studied by advanced surface science tools, reveals various phenomena occurring in different temperature ranges. In the room temperature (RT) < T < 460 K range, the deposited Fe atoms assemble as heterogeneous Fe and FeOx nanoparticles (NPs), templated by the ordered array of defects (troughs and picoholes) of the oxide film. At 460 < T < 810 K, FeOx NPs become predominant, and a metastable FeOx/TiOx mixed oxide is formed, assisted by the interdiffusion of Fe through the oxide into the Pt substrate, which triggers the z'-TiOx structure transformation into a different TiOx phase with a hexagonal pattern. At 810 < T < 1000 K, a Fe-mediated extraction of Pt produces Pt(111) islands, surrounded and partly encapsulated by the same z'-TiOx phase, demonstrating the intrinsic high stability of the ultrathin oxide film. This represents one of the first examples of a phase transformation in a ultrathin oxide layer induced by an external metal deposit.
Inglese
Artiglia, L., Cavaliere, E., Rizzi, G., Gavioli, L., Granozzi, G., Probing Transformations of Relevance in Catalysis on a Single Oxide Layer: Fe on TiOx/Pt(111), <<THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS>>, 2010; 2010 (1): 1660-1665. [doi:10.1021/jz100511s] [http://hdl.handle.net/10807/6150]
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10807/6150
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