摘要
以Ce（NO3）3.6H2O,ZrO（NO3）2.2H2O和Bi（NO3）3.5H2O为原料,氨水为沉淀剂,双氧水为氧化剂,在pH值为9.5~10.5条件下,采用氧化共沉淀法制备了不同比例组成的复合氧化物Ce1-x-yZrxBiyOσ。通过XRD,BET和Raman表征可知,该法制备的样品550℃焙烧后均可形成固溶体,当x〉0.15,y〉0.2时,高温焙烧后易分相。H2-TPR和CO脉冲测试结果显示Ce0.65Zr0.15Bi0.2Oσ较易被还原,且1050℃焙烧4 h后储氧量仍可达625μmo.l（g cat）-1,这是由于Bi3＋取代了Ce0.65Zr0.15Bi0.2Oσ中部分Ce4＋和Zr4＋形成氧空位,增强了体相晶格氧的移动性,从而使Ce0.65Zr0.15Bi0.2Oσ固溶体中的Ce4＋和Bi3＋同时被还原。
Ce1-x-yZrxBiyOσ was prepared by oxidation-coprecipitation method at pH 9.5~10.5 with Ce（NO3） 3·6H2O,ZrO（NO3）2·2H2O and Bi（NO3）3·5H2O as raw materials,ammonia as precipitating agent,and hydrogen peroxide as oxidant.It was characterized by BET,X-ray diffraction analysis（XRD） and Raman.The results showed that the Ce1-x-yZrxBiyOσ had cubic fluorite structure.The temperature programmed reduction and CO pulses experiments showed that Ce0.65Zr0.15Bi0.2Oσ could easily be reduced,and after calcined at 1050 ℃ it still had high oxygen storage capacity（OSC） over 625 μmol·（g cat）-1.The reason for such a behavior was attributed to the formation of oxygen vacancies to enhance the oxide anion mobility by substituting Ce4＋ or Zr4＋ site with Bi3＋,and also to the simultaneous reduction of Ce4＋ and Bi3＋ in the Ce0.65Zr0.15Bi0.2Oσ solid solution.
出处
《中国稀土学报》
CAS
CSCD
北大核心
2010年第4期408-413,共6页
Journal of the Chinese Society of Rare Earths
基金
国家973计划项目(2010CB732300)资助
关键词
储氧性能
铈锆固溶体
氧化铋
稀土
oxygen storage capacity
Ce1-xZrxO2
Bi2O3
rare earths
