Determining the Co valence, particularly in Co-based nanocatalysts is a longstanding experimental challenge. In this paper, we utilize in situ electron energy-loss spectroscopy and first-principles density functional theory calculations to distinguish between metallic Co, , as well as CoO. More specifically, differences in the - and -edges are utilized to determine the Co valence in different Co-oxide particles. We will further demonstrate that while the metallic -ratio equals that of partially reduced , the near-edge fine-structure of the metallic -edge exhibits additional features not present in any Co-oxide. The origin of these features will be discussed. Based on our experimental and theoretical results, we will propose a fitting method to distinguish metallic Co from Co-oxides.
In situ electron energy loss spectroscopy study of metallic Co and Co oxides
Yuan Zhao, Theresa E. Feltes, John R. Regalbuto, Randall J. Meyer, Robert F. Klie; In situ electron energy loss spectroscopy study of metallic Co and Co oxides. J. Appl. Phys. 15 September 2010; 108 (6): 063704. https://doi.org/10.1063/1.3482013
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