Surface characterization of ordered intermetallic PtBi(0 0 1) surfaces by ultra-high vacuum–electrochemistry (UHV–EC)
- 作者：Jean Sanabria-Chinchilla ; Hideki Abe ; Francis J. DiSalvo ; Hé ; ctor D. Abruñ ; a
- 关键词：Ordered intermetallic phases ; PtBi(0 0 1) electrode ; UHV– ; EC ; Surface characterization ; Auger electron spectroscopy ; Low energy electron diffraction
- 刊名：Surface Science
- 出版年：2008
- 期刊代码：104_00396028
- 类别：ch
- 出版时间：15 May 2008
- 卷：602
- 期：10
- 页码：1830-1836
- 文件大小：527 K
摘要
Surface preparation and characterization of an ordered intermetallic PtBi(0 0 1) single crystal was performed by a combination of surface-sensitive electron spectroscopic techniques under ultra-high vacuum (UHV) conditions and conventional electrochemistry (EC). The atomic concentration of the clean surface was estimated (quantitative Auger analysis) as 54 at%Pt and 46 at%Bi; the LEED pattern exhibited a (1 × 1) structure. These results are in good agreement with expectations for a Pt-terminated PtBi(0 0 1) crystal surface. The electrochemical studies of the clean, well-ordered and smooth PtBi(0 0 1) single crystal were carried out in an H2SO4 supporting electrolyte and indicated that the electrode surface is Pt-terminated with a behavior similar to that of a pure Pt electrode. However, the intermetallic phase was found to be more prone to surface oxidation in the studied potential window (−0.30 V to +1.25 V vs. Ag/AgCl (sat’d NaCl)). Chemisorption of 
species was observed at potentials positive of the open circuit potential (OCP). Cycling in a supporting electrolyte gave rise to roughening of the electrode surface. This change is due to the presence of the chemisorbed species on the electrode surface.