柠檬酸溶胶凝胶法制备铈锆固溶体的物性和氧化还原特性研究

Preparation and Characterization of CeO_2-ZrO_2 Solid Solutions Prepared by Citric Acid Sol-Gel Method

以柠檬酸作为胶凝剂,采用溶胶凝胶法制备了一系列CexZr1-xO2复合氧化物,分别经600℃和900℃焙烧,应用XRD检测,发现均已形成铈锆固溶体.并应用BET、XRD和TPR对其表相、晶相结构和氧化还原性质进行了分析,发现随着固溶体中铈比例的增加,固溶体稳定性降低;其储氧量测定显示铈锆固溶体用作三效催化剂助剂的最佳比例为1∶1.经900℃高温焙烧以后,固溶体晶粒增大不明显,表明本方法适合制备高比表面积和高储氧量的铈锆固溶体;TPR还原峰温度降低,推测可能在于柠檬酸络合物完全分解所致.

A series of Cex Zr1-xO2 （x = 0.5,0.6 and 0.8）mixed oxides were prepared by citric acid sol-gel method with nitrate solution. It was shown that solid solution had formed after calcination at 600℃ by X-ray diffraction （XRD）. The surface and crystal structure of solid solutions were investigated by BET, oxygen storage capacity （OSC） and XRD after calcination at 600℃ and 900℃. The analysis of XRD showed that with the increase of xce, the specific surface area（SSA） and OSC of samples and the stability decreased. It was shown that the temperature of peak had decreased after calcination at 900℃ by H2-TPR because of complete decomposition of citric complex at the high temperature.