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本文用程序升温脱附方式对自制GR-50扩4工业銀催化剂表面上氧吸附、脱附特性作了实验考察。在20—330℃温度范围內,取得了其特征峰峰顶温度分別为120℃(Ⅰ)、230℃(Ⅱ)和300℃的TPD图谱。这三个特征峰各自对应氧分子的弱化学吸附(O_2)、活化的非解离吸附(O_2~-)及非活化的解离吸附(O~-)。同时,作了平行的反应动力学实验。通过研究二氯乙烷和助剂铯对TPD图谱中I、Ⅱ两个特征峰的影响以及对乙烯氧化性能的影响,确认TPD图谱上I、Ⅱ两个特征峰大小的变化和(O~-2/O~)之比以及催化反应选择性这三者之间的平行关系。
In this paper, temperature-programmed desorption of homemade GR-50 4 industrial silver catalyst surface oxygen adsorption and desorption characteristics were investigated. In the temperature range of 20-330 ℃, the TPD spectra of the products with the characteristic peak top temperature of 120 ℃ (Ⅰ), 230 ℃ (Ⅱ) and 300 ℃ were obtained. Each of the three characteristic peaks corresponds to weak chemisorption (O 2), activated non-dissociative adsorption (O 2 -) and non-activated dissociative adsorption (O ~) of oxygen molecules. At the same time, made a parallel reaction kinetics experiment. The effects of dichloroethane and cesium on the two characteristic peaks of I and II in TPD spectra and the influence on ethylene oxidation were studied. The changes of the two characteristic peaks (I and II) 2 / O ~) ratio and the selectivity of the catalytic reaction between the three parallel relationship.