摘要
采用共沉淀法制备铈锆铝复合氧化物CZ x A(Ce,Zr,Al摩尔比为1∶x∶2,其中x=0,0.5,1,1.5,2)新鲜样品,分别在空气和10%H 2/Ar气氛下进行热处理,利用X射线粉末衍射、N 2吸脱附BET法、O 2脉冲吸附、H 2程序升温还原(H 2 temperature-programmed reduction,H 2-TPR)等手段研究复合氧化物的结构及性能。结果表明:CZ x A系列样品随着Zr含量的增加,经1100℃还原热处理的CZ 1.5 A-H 2-1100和CZ 2A-H 2-1100样品没有观察到CeAlO 3晶相;其储氧量分别为713,548μmol·g-1,远大于CZA-H 2-1100的23μmol·g-1;H 2-TPR耗氢量分别为1995,2087μmol·g-1,而CZA-H 2-1100样品H 2-TPR耗氢量显著减小,仅为310μmol·g-1,CZ x A储氧性能受还原热处理时CeAlO 3形成的影响,与H 2-TPR耗氢量的变化结果相吻合。研究发现CA样品经还原热处理更易生成CeAlO 3,而在CA中掺杂一定量Zr元素后的CZ 1.5 A,CZ 2A样品能抑制CeAlO 3的形成,从而显著改善材料的储氧性能和H 2-TPR耗氢量,且铈锆铝材料经还原热处理,均具有更好的低温还原性能。
Ceria-zirconia-alumina composite oxides CZ x A(the molar ratios of Ce,Zr and Al are 1∶x∶2,x=0,0.5,1,1.5 and 2)fresh samples were prepared by the co-precipitation method.The samples were thermally aged in a flowing air atmosphere and in 10%H 2/Ar flow.The structure and performance of the composite oxides were studied by X-ray powder diffraction(XRD),N 2 adsorption-desorption(BET),oxygen storage capacity(OSC)measurements,and H 2 temperature-programmed reduction(H 2-TPR).The results show that for CZ x A samples,with the increase of the content of Zr,no CeAlO 3 phase is observed in the CZ 1.5 A-H 2-1100 and CZ 2A-H 2-1100 samples which are reductively aged at 1100℃;the oxygen storage capacity(OSC)is 713μmol·g-1 and 548μmol·g-1,respectively,far higher than the 23μmol·g-1 of CZA-H 2-1100;and the hydrogen consumption of H 2-TPR is 1995μmol·g-1 and 2087μmol·g-1,respectively,while the hydrogen consumption of CZA-H 2-1100 was significantly reduced to 310μmol·g-1.The OSC of CZ x A is affected by the formation of CeAlO 3 during the reductive treatment,which is consistent with the change result of the hydrogen consumption of H 2-TPR.It was found that CA samples are more likely to produce CeAlO 3 after reductive treatment,and the CZ 1.5 A and CZ 2A samples doped with a certain amount of Zr elements in CA can inhibit the formation of CeAlO 3,thus significantly improve the oxygen storage performance and the hydrogen consumption of H 2-TPR of the material.Furthermore,CZ x A have better reduction performance at low temperature after reductive treatment.
作者
杨黄根
谭喻方
韦庆敏
晏全
陈渊
朱立刚
覃利琴
肖益鸿
YANG Huang-gen;TAN Yu-fang;WEI Qing-min;YAN Quan;CHEN Yuan;ZHU Li-gang;QIN Li-qin;XIAO Yi-hong(Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology,Yulin Normal University,Yulin 537000,Guangxi,China;National Engineering Research Center of Chemical Fertilizer Catalyst,Fuzhou University,Fuzhou 350002,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2020年第12期90-96,共7页
Journal of Materials Engineering
基金
国家自然科学基金(21767029,51862034)
广西自然科学基金(2017GXNSFAA198197)
广西科技计划项目-重点研发计划(桂科AB18050004)。
