Combined XPS and in situ DRIRS study of mechanism of Pd–Fe/α-Al2O3 catalyzed CO coupling reaction to diethyl oxalate
Combined XPS and in situ DRIRS study of mechanism of Pd–Fe/α-Al2O3 catalyzed CO coupling reaction to diethyl oxalate
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DOI：
10.1016/j.molcata.2005.03.003
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发表时间：
2005-07
影响因子：
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通讯作者：
Gao Zhenghong;Liu Zhong-chen;H. Fei;Xu Genhui
中科院分区：
文献类型：
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作者：
Gao Zhenghong;Liu Zhong-chen;H. Fei;Xu Genhui
采用X射线光电子能谱（XPS）和原位漫反射红外光谱（DRIRS）技术，研究了常压气相条件下Pd-Fe/α-Al 2 O3催化剂上CO偶联制草酸二乙酯（DEO）的反应机理。采用原位DRIRS技术分别观察了一氧化碳和亚硝酸乙酯在催化剂上的吸附，并对亚硝酸乙酯吸附后的催化剂和原位反应后的催化剂进行了XPS表征。结果表明：（1）亚硝酸乙酯在催化剂表面发生解离吸附，导致Pd 0氧化为Pd 2+（催化剂上的活性组分）。（2）反应过程中涉及两个中间体钯配合物。据此提出了反应的机理步骤，并推测了两个中间体。
The mechanism for the reaction of CO coupling to diethyl oxalate (DEO) over Pd–Fe/α-Al2O3in gaseous phase at normal pressure was studied by X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared spectroscopy (DRIRS) techniques. The adsorption of two reactants, carbon monoxide and ethyl nitrite, on the catalyst was observed, respectively with in situ DRIRS as well as the catalysts after ethyl nitrite adsorption and after in situ reaction were also characterized by XPS measurement. These observational results show that (1) The ethyl nitrite on the catalyst surface has a dissociative chemisorption which leads to the oxidation of Pd0to Pd2+(active component on the catalyst). So the reaction is a redox process; (2) Two intermediates, palladium complexes, in the reaction process are involved. From this, the mechanism steps of the reaction were proposed and the two intermediates were inferred.