Nanoscopic Observation of Strong Chemical Interaction between Pt and Tin Oxide
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- 作者：Naoto Kamiuchi ; Toshiaki Matsui ; Ryuji Kikuchi ; Koichi Eguchi
- 刊名：Journal of Physical Chemistry C
- 出版年：2007
- 出版时间：November 8, 2007
- 年：2007
- 卷：111
- 期：44
- 页码：16470 - 16476
- 全文大小：973K
- 年卷期：v.111,no.44(November 8, 2007)
- ISSN：1932-7455
文摘
Platinum catalysts supported on tin oxide were prepared by the impregnation method and were treated inseveral conditions. The change of their structure by the treatment was investigated by X-ray diffraction,X-ray photoelectron spectroscopy, and transmission electron microscopy. In the as-prepared catalyst, platinumparticles with their mean size of ca. 3 nm were highly dispersed on SnO2 supports. After the treatment inreduction atmosphere, the intermetallic compounds ascribed to PtSn and Pt3Sn were formed, and the growthof particle by aggregation was observed. Moreover, the particles with core-shell nanostructure were observedin the catalyst reduced at higher temperatures. It was revealed that the core-shell structure was formed bythe phase separation of Sn species from the intermetallic compound particles when the catalyst was treatedby mild reoxidation such as exposure to air. On the other hand, after the reoxidation treatment, the meanparticle size of the metal particle became smaller and crystallized in the unique particle morphology. Afterreoxidation at higher temperatures, the intermetallic compounds disappeared, and morphology of platinumparticles observed in the as-prepared catalyst was regenerated. These structural changes in the interface betweenplatinum and SnO2 should be related to the unusual CO adsorptive property of Pt/SnO2.