Local structure of the zeolitic catalytically active site during reaction.
Local structure of the zeolitic catalytically active site during reaction.
复制标题
反应过程中沸石催化活性位点的局部结构。
DOI：
10.1021/ja031755j
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发表时间：
2004
影响因子：
15
通讯作者：
R. Prins
中科院分区：
文献类型：
--
作者：
J. V. van Bokhoven;A. V. D. van der Eerden;R. Prins
检测了酸性沸石催化反应过程中催化活性中心的结构变化。沸石的布仑斯台德活性中心的局部结构是一个扭曲的四面体配位铝，具有三个短的和一个长的铝-氧键。使用原位Al K边X射线吸收光谱，在乙烯齐聚反应中的反应中间体的吸附改变了催化活性位点的局部结构，长铝氧键被部分弛豫。在越来越高的温度下，催化剂的大量焦化使布朗斯台德酸位点从反应性中间体中释放出来，恢复不对称配位。这些测量结果表明，原位铝K边缘光谱的应用提供了催化作用过程中的沸石催化活性位点的结构的基本见解。
The structural changes of the catalytic active site that occur during catalytic reaction in an acidic zeolite are detected. The local structure of the zeolitic Brønsted active site is a distorted tetrahedrally coordinated aluminum that has three short and one long aluminum-oxygen bond. Using in situ Al K edge X-ray absorption spectroscopy, the adsorption of a reactive intermediate in the oligomerization of ethene changed the local structure of the catalytic active site; the long aluminum oxygen bond is partially relaxed. At increasingly higher temperature, extensive coking of the catalyst frees the Brønsted acid site from the reactive intermediate, restoring the asymmetric coordination. These measurements show that application of in situ Al K edge spectroscopy provides fundamental insight into the structure of zeolitic catalytically active sites during catalytic action.