The effect of ZnO in methanol synthesis catalysts on Cu dispersion and the specific activity
The effect of ZnO in methanol synthesis catalysts on Cu dispersion and the specific activity
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DOI：
10.1023/a:1019000927366
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发表时间：
1998-01-01
影响因子：
2.8
通讯作者：
Nakamura, J
中科院分区：
文献类型：
--
作者：
Fujitani, T;Nakamura, J
采用共沉淀法制备了Cu/ZnO催化剂，通过测定Cu的比表面积、CO2加氢合成甲醇的比活性和XRD，研究了ZnO对Cu/ZnO催化剂的影响。尽管如通常已知的，Cu表面积随着ZnO含量（0-50重量%）的增加而增加，但是具有各种Cu：ZnO重量比的Cu/ZnO催化剂的比活性大于不含ZnO的Cu催化剂的比活性。这些事实清楚地表明，ZnO在Cu/ZnO催化剂中的作用可以归因于Cu分散和比活性的增加。XRD结果表明，Cu/ZnO催化剂的Cu颗粒中形成了Cu-Zn合金，从而提高了催化剂的比活性。因此，认为除了在甲醇合成期间催化几个氢化步骤的金属铜原子之外，Cu-Zn表面合金或Cu-Zn位点是甲醇合成的活性位点。此外，通过金绿铜矿前体的共沉淀法的优点归因于Cu表面积和比活性的改善。
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.