Evolution of the Atomic Structure of Ceria-Supported Platinum Nanocatalysts: Formation of Single Layer Platinum Oxide and Pt–O–Ce and Pt–Ce Linkages
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- 作者：Leon A. AvakyanNatalia A. Kolpacheva ; Ekaterina V. Paramonova ; Jagdeep SinghUrs Hartfelder ; Jeroen A. van Bokhoven ; Lusegen A. Bugaev
- 刊名：Journal of Physical Chemistry C
- 出版年：2016
- 出版时间：December 15, 2016
- 年：2016
- 卷：120
- 期：49
- 页码：28057-28066
- 全文大小：648K
- ISSN：1932-7455
文摘
Depending on platinum loading and gas environment vastly different platinum structures in Pt/ceria were observed by Pt L<sub>3sub>-edge extended X-ray absorption (EXAFS) and X-ray absorption near-edge (XANES) spectroscopies. Calcination of highly loaded platinum (4 wt %) yielded stacked layers of α-PtO<sub>2sub>. The low platinum-loaded sample (2 wt %), obtained by leaching, consisted of a single layer of α-PtO<sub>2sub> bonded to the support by Pt–O–Ce linkages. Reduction of the platinum oxide by exposure to a carbon monoxide and hydrogen (PROX) gas mixture led to complete metal reduction at temperatures above 540 K. Under these conditions platinum–cerium bonds with a distance of 2.4 Å were detected and particles of 0.8 and 0.6 nm for the high-loaded and low-loaded Pt/ceria samples, respectively.