Subsecond and in Situ Chemical Speciation of Pt/Al2O3 during Oxidation–Reduction Cycles Monitored by High-Energy Resolution Off-Resonant X-ray Spectroscopy
详细信息 查看全文
- 作者：Jakub Szlachetko ; Davide Ferri ; Valentina Marchionni ; Anastasios Kambolis ; Olga V. Safonova ; Christopher J. Milne ; Oliver Kr?cher ; Maarten Nachtegaal ; Jacinto Sá
- 刊名：Journal of the American Chemical Society
- 出版年：2013
- 出版时间：December 26, 2013
- 年：2013
- 卷：135
- 期：51
- 页码：19071-19074
- 全文大小：268K
- ISSN：1520-5126
文摘
We report an in situ time-resolved high-energy resolution off-resonant spectroscopy study with subsecond resolution providing insight into the oxidation and reduction steps of a Pt catalyst during CO oxidation. The study shows that the slow oxidation step is composed of two characteristic stages, namely, dissociative adsorption of oxygen followed by partial oxidation of Pt subsurface. By comparing the experimental spectra with theoretical calculations, we found that the intermediate chemisorbed O on Pt is adsorbed on atop position, which suggests surface poisoning by CO or surface reconstruction.