Multielement Activity Mapping and Potential Mapping in Solid Oxide Electrochemical Cells through the use of operando XPS

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• 作者：Chunjuan Zhang ; Michael E. Grass ; Yi Yu ; Karen J. Gaskell ; Steven C. DeCaluwe ; Rui Chang ; Gregory S. Jackson ; Zahid Hussain ; Hendrik Bluhm ; Bryan W. Eichhorn ; Zhi Liu
• 刊名：ACS Catalysis
• 出版年：2012
• 出版时间：November 2, 2012
• 年：2012
• 卷：2
• 期：11
• 页码：2297-2304
• 全文大小：471K
• 年卷期：v.2,no.11(November 2, 2012)
• ISSN：2155-5435

文摘

Spatially resolved ambient pressure X-ray photoelectron spectroscopy has been used to measure and visualize regions of electrochemical activity, local surface potential losses, overpotentials, and oxidation state changes on single sided ceria/yttria-stabilized zirconia (YSZ)/Pt solid oxide electrochemical cells. When hydrogen electro-oxidation (negative applied bias) or water electrolysis (positive applied bias) is promoted on the ceria electrocatalyst, the Ce³⁺/Ce⁴⁺ ratios shift away from equilibrium values and thereby demarcate electrochemically active regions on the ceria electrode. In addition to the ceria oxidation state shifts, inactive surface impurities with high photoelectron cross sections, such as Si, can provide local markers of activity through chemical and surface potential mappings under various electrochemical conditions. Localized removal of chemically active carbonaceous surface impurities also reveals regions of electrochemical oxidation activity on the ceria electrode. Finally, we show that electrochemical polarization of solid oxide electrochemical cells under different gas environments is used to control the ceria surface chemical state and oxygen vacancy density.

Keywords:

ambient pressure XPS; ceria; solid oxide electrochemical cell; operando