【摘要】 采用沉淀前驱物混合法制备铈锆铝复合氧化物（CZ+A（pm））和沉淀机械研磨混合法制备铈锆铝复合氧化物（CZ+A（mm））（x（Ce）∶x（Zr）∶x（Al）=1∶1∶2）。将样品分别在空气和10%H₂/Ar气氛下进行热处理,利用X射线粉末衍射（XRD）、N₂吸脱附（BET）、O₂脉冲吸附、H₂程序升温还原（H₂-TPR）等手段研究了复合氧化物的结构及性能。结果表明,CZ+A（pm）、CZ+A（mm）新鲜样品经1 100℃还原热处理后的CZ+A（pm）-H₂-1 100样品的XRD图谱出现较多且尖锐的归属于CeAlO₃的衍射峰,而CZ+A（mm）-H₂-1 100样品没有观察到CeAlO₃晶相;其储氧量分别为157和773μmol/g,均大于CZA-H₂-1 100的23.2μmol/g;H₂-TPR耗氢量分别为960和1 916μmol/g,而CZA-H₂-1 100样品H₂-TPR耗氢量仅为310μmol/g,CZ+A（pm）储氧性能受还原热处理时CeAlO₃形成的影响,与还原性能的变化结果相吻合。研究发现,铈锆铝复合氧化物中CZ+A（pm）样品的铈锆和氧化铝粒子尺度较小,相互之间接触较紧密,使得CeO₂和Al₂O₃较易发生固相化合反应生成CeAlO₃,而CZ+A（mm）样品中铈锆和氧化铝粒子更大,相互之间间隔更远,经还原热处理时能抑制CeAlO₃的形成,从而改善材料在还原气氛下的储氧性能和还原性能。更多还原

【Abstract】 Ceria-zirconia-alumina composite oxides CZ+A（pm） and CZ+A（mm）（the molar ratio of Ce, Zr and Al was 1∶1∶2） were prepared by the mixing precursor of precipitates and the mixing precipitates mechanically methods, respectively. The samples were thermally aged in a flowing air atmosphere and in 10% H₂/Ar flow. The structure and performance of the composite oxides were studied by X-ray diffraction（XRD）, N₂ adsorption-desorption（BET）, oxygen storage capacity（OSC） measurements, and H₂ temperature-programmed reduction（H₂-TPR）. The results show that the XRD patterns of CZ+A（pm）-H₂-1 100 exhibited many sharp diffraction peaks attributed to CeAlO₃, but CZ+A（mm）-H₂-1 100 reductively aged at 1 100 ℃ did not appear CeAlO₃ phase. The oxygen storage capacity（OSC） was 157 and 773 μmol/g, respectively, which were far higher than the 23.2 μmol/g of CZA-H₂-1 100, and the hydrogen consumption of H₂-TPR was 960 and 1 916 μmol/g, respectively, while the hydrogen consumption of CZA-H₂-1 100 was significantly reduced to 310 μmol/g. The OSC of CZ+A（pm） was affected by the formation of CeAlO₃ during the reductive treatment, which was consistent with the change result of reductive performance. It was found that CeO₂ and Al₂O₃ in CZ+A（pm） samples, with the particles of cerium-zirconium and alumina being small in scale and close in contact with each other, were more likely to produce CeAlO₃ through solid-phase combination reaction. However, the reductive treatment of CZ+A（mm） samples, for the cerium-zirconium and alumina particles being larger and farther apart, could inhibit the formation of CeAlO₃, thus significantly improving the oxygen storage performance and reductive performance of the material in the reduction atmosphere.更多还原