Operando Analysis of NiFe and Fe Oxyhydroxide Electrocatalysts for Water Oxidation: Detection of Fe4+ by M枚ssbauer Spectroscopy

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• 作者：Jamie Y. C. Chen ; Lianna Dang ; Hanfeng Liang ; Wenli Bi ; James B. Gerken ; Song Jin ; E. Ercan Alp ; Shannon S. Stahl
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：December 9, 2015
• 年：2015
• 卷：137
• 期：48
• 页码：15090-15093
• 全文大小：347K
• ISSN：1520-5126

文摘

Nickel鈥搃ron oxides/hydroxides are among the most active electrocatalysts for the oxygen evolution reaction. In an effort to gain insight into the role of Fe in these catalysts, we have performed operando M枚ssbauer spectroscopic studies of a 3:1 Ni:Fe layered hydroxide and a hydrous Fe oxide electrocatalyst. The catalysts were prepared by a hydrothermal precipitation method that enabled catalyst growth directly on carbon paper electrodes. Fe⁴⁺ species were detected in the NiFe hydroxide catalyst during steady-state water oxidation, accounting for up to 21% of the total Fe. In contrast, no Fe⁴⁺ was detected in the Fe oxide catalyst. The observed Fe⁴⁺ species are not kinetically competent to serve as the active site in water oxidation; however, their presence has important implications for the role of Fe in NiFe oxide electrocatalysts.