Study of the structural modifications induced by reducing treatments on a Pd/Ce0.8Tb0.2O2-x/La2O3-Al2O3 catalyst by means of X-ray diffraction and electron microscopy techniques
Study of the structural modifications induced by reducing treatments on a Pd/Ce0.8Tb0.2O2-x/La2O3-Al2O3 catalyst by means of X-ray diffraction and electron microscopy techniques
复制标题
利用 X 射线衍射和电子显微镜技术研究 Pd/Ce0.8Tb0.2O2-x/La2O3-Al2O3 催化剂还原处理引起的结构修饰
DOI：
10.1021/cm011260y
复制
发表时间：
2002
期刊：
影响因子：
--
通讯作者：
H. Vidal
中科院分区：
文献类型：
--
作者：
S. Bernal;J. Calvino;G. Cifredo;D. Finol;J. M. Gatica;C. Kiely;C. López;J. G. Zheng;H. Vidal
Rietveld 分析的 X 射线衍射、EDS、HREM 和 CO 氧化实验已用于研究 Pd/Ce0.8Tb0.2O2-x/La2O3−Al2O3 催化剂的纳米级演化随还原温度的变化。在高达 700 °C 的温度下，Pd 和 Ce0.8Tb0.2O2-x 混合氧化物均以纳米级颗粒的形式存在，并良好地分散在 La 改性氧化铝载体上。在 900 °C 还原后，金属 Pd 颗粒发生严重烧结，同时形成钙钛矿相 LnAlO3，其中三价稀土离子含量不同（Ln3+ = La3+、Ce3+ 和 Tb3+）。随着还原温度的升高，观察到 CO 氧化反应催化剂的平行失活。
X-ray diffraction with Rietveld analysis, EDS, HREM, and CO oxidation experiments have been used to study the nanoscale evolution with reduction temperature of a Pd/Ce0.8Tb0.2O2-x/La2O3−Al2O3 catalyst. Up to 700 °C, both Pd and the Ce0.8Tb0.2O2-x mixed oxide are present as nanosized particles that are well-dispersed over the La-modified alumina support. After reduction at 900 °C, severe sintering of the metallic Pd particles occurs, along with the formation of a perovkite phase LnAlO3 with variable content of trivalent lanthanide ions (Ln3+ = La3+, Ce3+, and Tb3+). Parallel deactivation of the catalyst for the CO oxidation reaction is observed upon increasing reduction temperature.