Evolution of the Chemical Valence on the Surface of the Cerium—Tungsten Electrode
Cerium tungsten electrode was heated in the analysis chamber of X-ray photoelectron spectroscopy (XPS) system at different temperatures. The evolution of the valence state of the main elements on the surface of the cerium tungsten electrode material was monitored by in suit XPS. It was found that the cerium on the surface of the sample in the initial state was mainly in the form of Ce4+ and Ce3+. During the heating process, Ce 3d core energy level spectrum changed. With the temperature rised, the content of Ce4+ in the samples decreased gradually. It can be seen that a part of Ce4+ is converted to Ce3+ during the heating process of the cerium tungsten electrode material. That means cerium in the cerium tungsten electrode material has a tendency to be restored, this will promote the electron emission and enhance the performance of the electrode material.
KeywordsTungsten cathode X-ray photoelectron spectroscopy (XPS) Cerium Reduction
This work was supported by The National Key Research and Development Program of China (2017YFB0305601).
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