制备方法对铈锆铝复合氧化物还原热处理性能的影响  

Effect of preparation method on the performance of CeO2-ZrO2-Al2O3 composite oxide after reductive treatment

作　　者：杨黄根 晏全[1] 韦庆敏[1] 陈渊[1] 朱立刚[1] 覃利琴[1] 肖益鸿[2] YANG Huanggen;YAN Quan;WEI Qingmin;CHEN Yuan;ZHU Ligang;QIN Liqin;XIAO Yihong(Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology,Yulin Normal University,Yulin 537000,China;National Engineering Research Center of Chemical Fertilizer Catalyst,Fuzhou University,Fuzhou 350002,China)

机构地区：[1]玉林师范学院广西农产资源化学与生物技术重点实验室,广西玉林537000 [2]福州大学化肥催化剂国家工程研究中心,福州350002

出　　处：《功能材料》2019年第11期11182-11189,共8页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(21767029,51862034);广西自然科学基金资助项目(2017GXNSFAA198197);广西中青年高校教师基础能力提升资助项目(2017KY0536);玉林师范学院校级科研资助项目(2017YJKY24)

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。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.

关 键 词：铈锆铝复合氧化物CZ+A(pm)和CZ+A(mm) 还原热处理 CeAlO3 储氧性能 还原性能 

分 类 号：O643[理学—物理化学]