The effect of ZnO in methanol synthesis catalysts on Cu dispersion and the specific activity

被引:212
作者
Fujitani, T [1 ]
Nakamura, J
机构
[1] Natl Inst Resources & Environm, Tsukuba, Ibaraki 305, Japan
[2] Univ Tsukuba, Inst Mat Sci, Tsukuba, Ibaraki 305, Japan
关键词
methanol synthesis; Cu/ZnO catalyst; hydrogenation of CO2; role of Zn;
D O I
10.1023/A:1019000927366
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The effect of ZnO in Cu/ZnO catalysts prepared by the coprecipitation method has been studied using measurements of the surface area of Cu, the specific activity for the methanol synthesis by hydrogenation of CO2, and XRD. Although the Cu surface area increases with increasing ZnO content (0-50 wt%) as is generally known, the specific activity of the Cu/ZnO catalysts with various weight ratios of Cu:ZnO is greater than that of a ZnO-free Cu catalyst. These facts clearly indicate that the role of ZnO in Cu/ZnO catalysts can be ascribed to both increases in the Cu dispersion and the specific activity. The XRD results indicate the formation of a Cu-Zn alloy in the Cu particles of the Cu/ZnO catalysts, leading to the increase in specific activity. It is thus considered that the Cu-Zn surface alloy or a Cu-Zn site is the active site for methanol synthesis in addition to metallic copper atoms that catalyze several hydrogenation steps during the methanol synthesis. Furthermore, the advantage of the coprecipitation method through a precursor of aurichalcite is ascribed to both improvements in the Cu surface area and the specific activity.
引用
收藏
页码:119 / 124
页数:6
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