首页 | 本学科首页   官方微博 | 高级检索  
     检索      

Cu-ZnO-Al2O3甲醇合成催化剂活性组分的高温动态变化
引用本文:马洪涛,邓国才,包信和.Cu-ZnO-Al2O3甲醇合成催化剂活性组分的高温动态变化[J].催化学报,2001,22(3):259-262.
作者姓名:马洪涛  邓国才  包信和
作者单位:1. 中国科学院大连化学物理研究所;南开大学化学系
2. 南开大学化学系,
3. 中国科学院大连化学物理研究所
摘    要: 采用XRD和XPS方法考察了Cu-ZnO-Al2O3甲醇合成催化剂在高温焙烧、还原和反应过程中活性组分的动态变化.结果表明,高温焙烧可造成活性组分晶粒的生长,ZnO晶粒比CuO晶粒更易于生长和在表面富集,从而引起Cu/Zn比下降.在还原和反应过程中,一方面H与Cu相互作用引起的Cu粒子表面自由能的降低远大于H对ZnO的影响,使得Cu粒子的生长在热力学上更有利;另一方面,由于Cu的熔点较低,造成Cu粒子的表面迁移活化能较低,表面扩散系数较高,受表面扩散所支配的粒子移动引起的晶粒生长较快,而ZnO由于熔点较高,在氢气气氛中粒子生长较慢.与焙烧后的催化剂相比,还原及反应后的催化剂表面Cu/Zn比明显增大.

关 键 词:甲醇合成    氧化锌  氧化铝  负载型催化剂  晶粒生长  活性组分
文章编号:0253-9837(2001)03-0259-04
收稿时间:2001-06-25
修稿时间:2000年7月31日

Dynamic Transformation of Active Components in Cu-ZnO-Al2Os Catalyst for Methanol Synthesis at High Temperature
MA Hongtao ,DENG Guocai ,BAO Xinhe.Dynamic Transformation of Active Components in Cu-ZnO-Al2Os Catalyst for Methanol Synthesis at High Temperature[J].Chinese Journal of Catalysis,2001,22(3):259-262.
Authors:MA Hongtao  DENG Guocai  BAO Xinhe
Institution:MA Hongtao 1,2 *,DENG Guocai 2,BAO Xinhe 1
Abstract:The dynamic transformation of active components in the Cu ZnO Al 2O 3 catalyst for methanol synthesis during the calcination, reduction and reaction was investigated by XRD and XPS methods. The results showed that, when the catalyst was calcined in air, the particle size of the components increases with increasing calcination temperature, ZnO crystal grain grows faster than CuO crystal grain and aggregates on the surface of the catalyst, resulting in a decrease of the surface Cu/Zn ratio. During the reduction and reaction, the decrease in surface free energy of Cu crystal grain due to the interaction between hydrogen and Cu particle is more than that of ZnO crystal grain, which is favorable for growth of the Cu crystal grain. The lower melting point of Cu makes the Cu particles own a lower activation energy of surface migration and a higher surface diffusion coefficient, therefore the growth of the Cu crystal grain controlled by surface diffusion is faster. But the ZnO crystal grain grows slower in the reducing atmosphere because of its higher melting point. In comparison with the calcined catalyst, the surface Cu/Zn ratio of the catalyst after reduction and reaction increases obviously.
Keywords:methanol synthesis  copper  zinc oxide  alumina  supported catalyst  growth of crystal grain  active component  migration
本文献已被 CNKI 万方数据 等数据库收录!
点击此处可从《催化学报》浏览原始摘要信息
点击此处可从《催化学报》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号