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钙钛矿型 LaCoO3-δ和 La1-xSrxCo O3 -δ纳米粒子的 XPS表征
XPS CHARACTERIZATION OF NANOMETER LaCoO 3-δ AND La 1-x Sr xCoO 3-δ
【摘要】 采用XPS等手段对LaCoO3-δ和La1-xSrxCoO3-δ纳米粒子进行了表征。结果显示,随LaCoO3-δ纳米粒子粒径的减小,一方面表面钴浓度增加,另一方面,表面CoO键的离子性增强和表面氧空位浓度增加。此二者共同导致LaCoO3-δ对一氧化碳氧化的催化活性随其粒径减小而明显增大。LaCoO3-δ纳米粒子中镧被锶部分取代后,其表面结构发生了变化,并导致对一氧化碳氧化的催化活性显著提高
【Abstract】 Nanometer LaCoO 3-δ and La 1-x Sr xCoO 3-δ with perovskite structure were characterized by XPS technique The results showed that with the decrease of the particle size of LaCoO 3-δ , on one hand, the surface concentration of Co 3+ increesed, on the other hand, the ionicity of surface CoO bond and surface oxygen vocancy concentration increased Both of them enhanced catalytic activity of LaCoO 3-δ for carbon monoxide oxidation with the decrease of its particle size The substitution of strontium for lanthanum in LaCo O 3-δ leaded to the change of its surface structure, which significantly increased its catalytic activity for carbon monoxide oxidation The binding energy of chemical adsorbed oxygen and the ratio of O C A /O C A +O L(O C A : chemical adsorbed oxygen, O L: lattice oxygen on surface) did not depend on the variation of particle size and the substitution of strontium for lanthanum in LaCoO 3-δ
【Key words】 perovskite-type oxide; nanometer particle; XPS; catalytic oxidation;
- 【文献出处】 燃料化学学报 ,JOURNAL OF FUEL CHEMISTRY AND TECHNOLOGY , 编辑部邮箱 ,1999年04期
- 【分类号】O643.36
- 【被引频次】33
- 【下载频次】400