...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Redox properties of doped and supported copper-ceria catalysts
【24h】

Redox properties of doped and supported copper-ceria catalysts

机译：掺杂和负载型铜-二氧化铈催化剂的氧化还原性能

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Copper-doped ceria catalysts feature in a variety of catalytic reactions. One important application is selective hydrogen combustion via oxygen exchange, which forms the basis of cyclic oxidative dehydrogenation. This paper describes the synthesis of monophasic ( doped) and biphasic ( supported) Cu-ceria catalysts, that are then characterized using a combination of temperature programmed reduction (TPR) and X-ray diffraction (XRD) methods. The catalysts are analyzed both as fresh samples and after redox cycling at 550-800 degrees C. TPR and XRD characterization clarify the role of the active sites on the catalyst surface and the copper-ceria interactions. Depending on the catalyst type, reduction occurs at similar to 110 degrees C, similar to 150 degrees C, or similar to 190 degrees C. The reduction at 110 degrees C is ascribed to highly dispersed copper species doped in the ceria lattice, and that at 190 degrees C to CuO crystallites supported on ceria. Remarkably, both types converge to the 150 degrees C feature after redox cycling. The reduction temperature of the doped catalyst increases after redox cycling, indicating that stable Cu clusters form at the surface. Conversely, the reduction temperature of the "supported" catalyst decreases after redox cycling, and the CuO crystallites disappear. With this knowledge, a copper-doped ceria catalyst is analyzed after application in selective hydrogen combustion (16 consecutive redox cycles at 550 degrees C). No CuO crystallites are observed, and the sample reduces at similar to 110 degrees C. This suggests that copper-doped ceria is the active oxygen exchange phase in selective hydrogen combustion.
机译：铜掺杂的二氧化铈催化剂具有多种催化反应的特征。一种重要的应用是通过氧交换的选择性氢燃烧，这构成了循环氧化脱氢的基础。本文介绍了单相（掺杂）和双相（氧化铈）二氧化铈催化剂的合成方法，然后结合程序升温还原（TPR）和X射线衍射（XRD）方法对其进行了表征。催化剂既可以作为新鲜样品进行分析，也可以在550-800摄氏度的氧化还原循环后进行分析。TPR和XRD表征明确了催化剂表面活性位的作用以及铜-二氧化铈的相互作用。根据催化剂类型的不同，还原反应的发生温度接近110摄氏度，150摄氏度或190摄氏度。110摄氏度的还原归因于掺杂在二氧化铈晶格中的高度分散的铜物质，以及190摄氏度的氧化铈负载的CuO微晶。值得注意的是，两种类型在氧化还原循环后都收敛到150摄氏度。氧化还原循环后，掺杂催化剂的还原温度升高，表明在表面形成了稳定的铜簇。相反，在氧化还原循环后，“负载型”催化剂的还原温度降低，并且CuO微晶消失。以此知识，在选择性氢气燃烧（550℃下连续16次连续氧化还原循环）后，对掺杂铜的二氧化铈催化剂进行了分析。没有观察到CuO微晶，并且样品在约110℃下还原。这表明掺杂铜的二氧化铈是选择性氢燃烧中的活性氧交换相。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号