物理化学学报 >> 1988, Vol. 4 >> Issue (02): 172-176.doi: 10.3866/PKU.WHXB19880211

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用XPS对La1-xSrxCoO3的研究——Ⅲ. LaCoO3的还原及表面状态

胡刚; 张艽   

  1. 中国科学院长春应用化学研究所
  • 收稿日期:1986-05-14 修回日期:1987-06-18 发布日期:1988-04-15
  • 通讯作者: 胡刚

AN X-RAY PHOTOELECTRON SPECTROSCOPY STUDY OF La1-xSrxCoO3 Ⅲ. THE REDUCTION AND SURFACE STATE OF LaCoO3

Hu Gang*; Zhang Peng   

  1. Changchun Institute of Applied Chemistry; Academia Sinica
  • Received:1986-05-14 Revised:1987-06-18 Published:1988-04-15
  • Contact: Hu Gang

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摘要： 本文用XPS研究了LaCoO_3在不同温度下氢气还原的情况, 并表征了钴的还原度。用X-光衍射了解还原后LaCoO_3为金属钴和La_2O_3二相。通过La 3d_(5/2)峰与其shake-up伴峰之间的距离确定La是以La(OH)_3的形式存在于表面。

Abstract: The reduction of LaCoO_3 has been studied by XPS. It is shown that the degree of reduction of cobalt is characterized by the peak intensity of shake-up satellite of Co 2p_(1/2) level. The reduction of Co~(3+) to Co~(2+) in LaCoO_3 is appeared at 400 ℃. When LaCoO_3 is reduced by H_2 at 600 ℃, the cobalt is converted into metallic form, meanwhile the structure of La_2O_3 is identified by X-ray diffraction. After reduction of LaCoO_3 the separation energy between La 3d_(5/2) level and its shake-up satellite peak is 3.1 eV and the intensity ratio of shake-up satellite to its parent peak for La 3d_(5/2) level is 0.76. These values are approximately sam e as those of La(OH)_3, but they are different from those of La_2O_3. Therefore, La(OH)_3 is formed on surface after reduction of LaCoO_3.