Reversible changes in the Pt oxidation state and nanostructure on a ceria-based supported Pt

Depending on the treatment conditions, platinum on a ceria-based oxide support changes reversibly from a small metallic nanoparticle to an oxidized monolayer, providing evidence of Pt–O–Ce bond formation in the latter. The Pt oxidation state and nanostructure on a ceria-based oxide support were char...

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Bibliographic Details
Published in:Journal of catalysis 2009-09, Vol.266 (2), p.182-190
Main Authors: Hatanaka, Miho, Takahashi, Naoki, Takahashi, Naoko, Tanabe, Toshitaka, Nagai, Yasutaka, Suda, Akihiko, Shinjoh, Hirofumi
Format: Article
Language:English
Subjects:
Automotive catalyst
Catalysis
Catalysts
Ceria
Chemical reactions
Chemistry
Exact sciences and technology
General and physical chemistry
Nanostructured materials
Oxidation
Platinum
Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
Transmission electron microscopy
X-ray photoelectron spectroscopy
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Summary:Depending on the treatment conditions, platinum on a ceria-based oxide support changes reversibly from a small metallic nanoparticle to an oxidized monolayer, providing evidence of Pt–O–Ce bond formation in the latter. The Pt oxidation state and nanostructure on a ceria-based oxide support were characterized after sequential oxidative, reductive, and re-oxidative treatments using X-ray photoelectron spectroscopy and transmission electron microscopy. The Pt oxidation state and nanostructure depended on the treatment atmosphere: an oxidized Pt monolayer spread along the primary particle surface of the ceria-based oxide support in the oxidized catalyst, whereas metallic Pt existed as particles of 1–2 nm in diameter in the reduced catalyst. Therefore, on the ceria-based oxide surface oxidized Pt formed a nanocomposite oxide with Ce under an oxidative atmosphere and reversibly changed to metallic Pt particles under a reductive atmosphere. The formation of this surface nanocomposite oxide is evidence of the strong interaction between oxidized Pt and CeO 2 that involves the formation of a Pt–O–Ce bond, which stabilizes Pt against sintering and redisperses agglomerated Pt particles under an oxidative atmosphere.
ISSN:0021-9517
1090-2694
DOI:10.1016/j.jcat.2009.06.005