物理化学学报 >> 1985, Vol. 1 >> Issue (05): 431-441.doi: 10.3866/PKU.WHXB19850506

研究论文 上一篇    下一篇

铜系催化剂低压合成甲醇的原位红外光谱研究

佟友东; 朱起明; 潘伟雄; 刘殿求; 杨光华   

  1. 清华大学 化学与化工系
  • 收稿日期:1984-12-20 修回日期:1985-05-10 发布日期:1985-10-15

“IN-SITU” IR SPECTROSCOPIC STUDIES ON METHANOL SYNTHESIS OVER Cu—ZnO—Al2O3 CATALYST

Tong Yudong; Zhu Qiming; Pan Weixiong; Liu Dianqiu; Yang Guanghua   

  1. Department of Chemistry and Chemical Engineering Tsinghua University
  • Received:1984-12-20 Revised:1985-05-10 Published:1985-10-15

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摘要： 本文运用本组设计和制作的高压原位红外池, 在反应条件下对铜催化剂的表面吸附态进行了原位检测。测到了表面吸附态和等的特征吸收峰。证实了CO和H_2在同一类活性中心上的竞争吸附, 并对其竞争吸附的能力作了考察。据此提出了该体系的吸附机理。在反应条件下, 检测到可判断为和M—O—CH_2OH等表面反应中间物的红外吸收峰。根据在不同温度和原料气组成下表面态的变化规律, 提出了合成反应是通过多途径进行以及CO_2对实现多途径起了重要作用的机理假设。

Abstract: "In-situ" infrared spectraphotometer cell designed and constructed by ourselves has been used to identify the surface species of CO and H_2 on copper-based cata lyst at elevated pressures and temperatures. Having conquered the difficulty due to the low transparency of Cu-ZnO-Al_2O_3 catalyst, the authors have obtained convin cible experimental results concerning surface intermediates on catalyst which can be used to speculate the reaction mechanism of methanol synthesis from syngas over Cu-ZnO-Al_2O_3 catalyst.
From the spectra of CO and H_2 on catalysts, it could be drawn that M—O—C—M and M—CO and M—H are surface species under reaction conditions. A competitive adsorption between CO and H_2 on the same sites has been verified, the adsorptive capacity of H_2 at equilibrium is greater than that of CO, indicating the ther-modynamic superiority of H_2 over CO. At higher temperatures, the dissociated adsorption of H_2 dominates the active centers. At low temperatures the active centers are entirely occupied by CO.
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