柠檬酸溶胶-凝胶法制备的Ce_(1-x)Zr_xO_2:结构及其氧移动性

Structure and Oxygen Mobility of Ce_(1-x)Zr_xO_2 Prepared by Citric Acid Sol-gel Method

采用XRF、XRD、Raman、XPS、H2-TPR以及与氩离子刻蚀相结合的XPS等表征技术对柠檬酸溶胶-凝胶法制备的Ce1-xZrxO2(0≤x≤1)样品的结构及其氧移动性进行了研究.结果表明,Ce1-xZrxO2样品的晶型结构对其中氧的移动性有明显影响.当x≤0.15时,Ce1-xZrxO2以立方CeO2相Ce-Zr-O固溶体存在,随着Zr含量的逐渐增加,CeO2晶胞体积减小、氧空位浓度增加,氧移动性逐渐增强;当x>0.15时,形成四方ZrO2相和立方CeO2相Ce-Zr-O固溶体的混合物,随着Zr含量的逐渐增加,四方ZrO2相的含量增加、氧空位浓度减小,氧移动性逐渐减弱.因此,Ce0.85Zr0.15O2样品具有最高的氧移动性.

The structure and oxygen mobility of Ce1-xZrxO2 （0 ≤ x ≤ 1） samples prepared by citric acid sol-gel method were characterized by XRF, XRD, Raman, XPS, Ar^＋ etching-XPS and H2-TPR. The data showed that the crystalline structure of Ce1-xZrxO2 can significantly affect the oxygen mobility. When x ≤ 0.15, the samples were found to exist as cubic Ce-Zr-O solid solutions. An increase in x resulted in a shrinking of the crystal unit volume, an increasing in the number of oxygen vacancies, and an increasing in the oxygen mobility as well. When x 〉 0.15, Ce1-xZrxO2 existed in a mixed phases of tetragonal and cubic Ce-Zr-O solid solutions; the percentage of tetragonal phase increased, oxygen vacancies decreased and oxygen mobility reduced with increasing x in these samples. Therefore, this present work shows that oxygen mobility in the Ce1-xZrxO2 sample is the highest.