کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
62582 | 47646 | 2009 | 9 صفحه PDF | دانلود رایگان |
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 CeO2 that involves the formation of a Pt–O–Ce bond, which stabilizes Pt against sintering and redisperses agglomerated Pt particles under an oxidative atmosphere.
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.Figure optionsDownload high-quality image (71 K)Download as PowerPoint slide
Journal: Journal of Catalysis - Volume 266, Issue 2, 10 September 2009, Pages 182–190