Temperature-programmed desorption and infrared study of CO and H2 adsorption on Cu/ZnO catalysts
Temperature-programmed desorption and infrared study of CO and H2 adsorption on Cu/ZnO catalysts
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Cu/ZnO 催化剂上 CO 和 H2 吸附的程序升温脱附和红外研究
DOI：
10.1016/0021-9517(88)90302-8
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
G. Griffin
中科院分区：
文献类型：
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作者：
D. L. Roberts;G. Griffin
我们结合吸附质吸收测量、程序升温解吸以及应用于 CO、H 2 和 O 2 吸附质的 FTIR 光谱，对通过多种方法制备的一系列 Cu ZnO 催化剂进行了表征。吸附的 CO 以多种吸附状态存在于还原催化剂上，这些状态通过 2104-2067 cm−1 范围内的不同振动频率来区分，并且以 10–16 kcal/mol 范围内的表观活化能解吸。当CO吸附在氧化催化剂上时，频率移至2136-2110 cm−1，最高解吸能增加至19 kcal/mol。对于吸附在还原催化剂上的H 2 ，观察到表观活化能为20-21 kcal/mol 的单一解吸状态。当H 2 吸附在氧化催化剂上时，该状态的解吸能增加至26-27 kcal/mol。对于还原催化剂，可逆的 CO 和 H 2 吸附量与在 98 K 下测量的 O 2 化学吸附量呈线性相关，CO、H 2 和 O 2 的相对吸收比例为 9:2:10。这些结果解释为表明 Cu 以金属簇的形式存在，暴露了大部分高指数表面平面，并且这些平面的化学行为是 与低折射率单晶面显着不同。
We have characterized a series of Cu ZnO catalysts prepared by several methods, using a combination of adsorbate uptake measurements, temperature-programmed desorption, and FTIR spectroscopy applied to CO, H 2, and O 2 adsorbates. Adsorbed CO is present on the reduced catalysts in several adsorption states which are distinguished by different vibrational frequencies in the range 2104-2067 cm− 1, and which desorb with apparent activation energies in the range 10–16 kcal/mol. When CO is adsorbed on oxidized catalysts, the frequencies shift to 2136-2110 cm− 1 and the highest desorption energy increases to 19 kcal/mol. For H 2 adsorbed on reduced catalysts, a single desorption state which has an apparent activation energy of 20–21 kcal/mol is observed. When H 2 is adsorbed on oxidized catalysts, the desorption energy of this state increases to 26–27 kcal/mol. For the reduced catalysts, the amounts of reversible CO and H 2 adsorbed are found to correlate linearly with the amount of O 2 chemisorption measured at 98 K, with relative uptakes for CO, H 2, and O 2 in the ratio 9: 2: 10. These results are interpreted to suggest that Cu is present as metallic clusters which expose a large fraction of high-index surface planes and that the chemical behavior of these planes is significantly different from that of low-index single crystal planes.