In Situ Probing of the Mechanisms of Coking Resistance on Catalyst-Modified Anodes for Solid Oxide Fuel Cells

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• 作者：Xiaxi Li ; Mingfei Liu ; Samson Y. Lai ; Dong Ding ; Mingyang Gong ; Jung-Pil Lee ; Kevin S. Blinn ; Yunfei Bu ; Zhihong Wang ; Lawrence A. Bottomley ; Faisal M. Alamgir ; Meilin Liu
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：February 10, 2015
• 年：2015
• 卷：27
• 期：3
• 页码：822-828
• 全文大小：499K
• ISSN：1520-5002

文摘

Coking is a major cause of performance degradation of Ni-based anodes in solid oxide fuel cells (SOFCs) powered by carbon-containing fuels. While modification of Ni surfaces using a thin coating of BaO, BaZr_0.9Y_0.1O_3鈥?i>d (BZY), and BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3鈥?i>d (BZCYYb) was reported to alleviate the problem, the mechanism is yet to be understood. In this study, in situ Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are used to probe the surface chemistry of BaO, BZY, and BZCYYb. Analyses of the time-resolved spectral features of C鈥揅 bonds, 鈭扥H groups, and 鈭扖O₃ groups reveal the interactions between surface functional groups and gas species (hydrocarbon, water steam, and CO₂). While the switching from 鈭扥H to 鈭扖O₃ groups is irreversible on BaO surfaces, it becomes reversible on both BZY and BZCYYb surfaces. Although the 鈭扥H mediated carbon removal is observed on the surfaces of all three catalysts, the 鈭扖O₃ is found effective for carbon removal only on the BZCYYb surface.