铈-锆-镧的掺杂对钴基催化剂性能的影响.pdf

第42卷第8期
无机盐工业
2010年8月
INORGANIC CHEMICALS INDUSTRY
21
铈一锆一镧的掺杂对钴基催化剂性能的影响
赫文秀'2,安胜利,张永强',王亚雄,许綬
(1.内蒙古科技大学化学与化工学院,内蒙古包头014010;2.北京科技大学冶金与生态工程学院)
摘要:采用共沉淀法制备添加铈、镧、镨的钴基催化剂,分别采用XRD、比表面积测试和粒度测试等方法对催
化剂进行了表征。结果表明;铈的添加量对催化剂有很大影响,催化剂的比表面积随着铈的掺杂量增多而増大,但
铈的掺杂量对催化剂颗粒的粒径基本没有影响。由于加入的铈与错形成铈锆氧化物固溶体,使得钴在催化剂表面
的分散度提高,但是铈锆氧化物固溶体的形成使得催化剂颗粒的硬度增加,颗粒度变大。XRD结果表明,铈与错形
成氧化物固溶体(Zo9:Ce_)O2,晶型为单斜型。钴以Co3O2的形式存在,La2O2的加入可以明显提高催化剂中Co
的分散度。
关键词:钴基催化剂;共沉淀法;固溶体;比表面积
中图分类号:TQ138.12文献标识码:A文章编号:1006-4990(2010)08-0021-03
Effect of Ce-zr-la doping on performance of cobalt based catalysts
He Wenxiu",An Shengli Zhang Yongqiang , Wang Yaxiong, Xu Xia
(1. School of Chemistry and Chemic gineering, in er Mongol e y of ene Technology, Baotou 014010, China
2. School of Metallurgical and Ecological Engineering, Beijing University of Science Technology)
Abstract: Cobalt-based catalyst doped with Ce, La, and Zr was prepared by co-precipitation method. The catalyst was
characterized by XRD, specific surface area, and particle size testing ctc.. Results showed that the doping amounts of Ce had
a great influence on the catalyst the catalysts specific surface area increased by doping more amounts of Ce, however, the
doping amounts of Ce nearly made little effect on particle size of the catalyst. Since doping Ce and Zr forming Ce and Zr
oxide solid solution, dispersion of Co was increased on the surface of catalyst, however, formation of solid solution of Ce and
Zr oxide made the hardness and particle size of catalyst both increase. XRD results showed that Ce and Zr turned into oxide
solid solution [i. e(Z1
)O2 with the
talline form. C
in the form of Cor O and the doping of
a] O could obviously enhance Co dispersion in the catalyst
Key words: cobalt based catalyst; co-precipitation method solid solution; specific surface area
煤制油有两种技术路线:一种是煤加氢直接液化剂。钴因为储量有限,所以具有工业应用价值的
化合成油品;另一种是煤先气化为合成气(CO+钴基催化剂多为负载型。为提高催化剂的性能,笔
H2),然后在催化剂作用下经 Fischer- Tropsch者通过共沉淀法制备Co基催化剂,研究Ce和La掺
(F-T)反应间接液化合成油品"り。Co基催化剂杂剂的加入对催化剂结构的影响“
和Fe基催化剂是常用的F-T合成催化剂。金属
1实验
铁储量比钻丰富、价格低廉,有利于生成低碳烯烃,
但Fe催化剂对水煤气变换反应具有高活性,链增长1.1制备过程
能力较差,反应温度高时催化剂易积炭和中毒。Co
按一定配比将配制好的La(NO3)3,Ce(NO3)3
加氢活性与Fe相似,具有较高的F-T链增长能Co(NO3)2饱和溶液加入到盛有ZO2的烧杯中混
力,反应过程中稳定且不易积炭和中毒,产物中含氧合,将混合溶液置于50℃恒温水浴中加热,边揽拌
化合物极少,水煤气变换反应不敏感等特点,因此边用恒流泵以7mL/mi速度滴加饱和碳酸氢铵溶
Co基催化剂被认为是F-T合成最有发展前途的催液,控制溶液的pH在7~8时,停止滴加碳酸氢铵
溶液,继续搅拌约2h使其沉淀完全;反应溶液过滤
基金项目:包头市科技计划项目(2008Y002-2)。
后在120℃下千燥,然后研磨1h,将研磨后的样