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Control of the structure of intrazeolite metal oxide clusters and their catalytic properties

沸石内金属氧化物簇结构的控制及其催化性能

基本信息

批准号：
09650860
负责人：
OKAMOTO Yasuaki
金额：
$ 2.18万
依托单位：
Shimane University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650860/
关键词：
Zeolite Metal oxide cluster XAFS Molecular design Catalysis Molybdenum oxide cluster Iron oxide cluster Metal sulfide cluster モリブデン酸化物鉄酸化物 X線吸収微細構造酸化鉄クラスター Co-Mo複合硫化物クラスター酸化モリブデンクラスター

项目摘要

Metal oxide catalysts are very important in industry. With supported oxide catalysts, it is well known that their activities and selectivities strongly depend on the support and the amount of loading, It is usually assumed that the dispersion of metal oxide species and, accordingly, the structure of the clusters modify their catalytic performances. However, they are not fully understood yet. It is required to understand the correlations between the structure of surface metal oxide species and their catalytic performances for rational and scientific design of highly efficient catalysts. In the present study, we tried to disclose the correlations between the catalyst performance and the structure of intrazeolite metal oxide clusters, the structure of which is considered to be well defined by confinement in a homogeneous skeleton of the host zeolite. We studied intrazeolite metal sulfide clusters as well. Mo oxide, Fe oxide, Co sulfide, Mo sulfide, and Go-Mo binary sulfide clusters were successfully constructed in zeolite pores, using metal carbonyl techniques. The structure of the clusters was determined by X-ray absorption spectra and FEFF codes. With the oxidation of ethanol, it was found that the activity increases with increasing size of the Mo oxide clusters. It was shown that Fe_6Ox clusters are formed in sodalite cage of the zeolite and that these clusters exhibit high activities for NOx abatement reactions. 'With metal sulfide clusters, it was revealed that Co1Mo_2S_6 clusters possessing a thiocubane structure were produced in the zeolite cages. It was shown that the Co-Mo binary sulfide clusters served a good model of the active sites of industrially paramount hydrotreating catalysts.

金属氧化物催化剂在工业上具有十分重要的意义。对于负载型氧化物催化剂，众所周知，它们的活性和选择性很大程度上取决于载体和负载量，通常认为金属氧化物的分散以及相应的簇结构改变了它们的催化性能。然而，它们还没有被完全理解。了解表面金属氧化物的结构与其催化性能之间的关系，是合理、科学设计高效催化剂的必要条件。在本研究中，我们试图揭示催化剂性能与沸石内金属氧化物团簇结构之间的相关性，沸石内金属氧化物团簇的结构被认为是通过限制在宿主沸石的均匀骨架中来定义的。我们也研究了沸石内金属硫化物簇。利用金属羰基技术，在沸石孔隙中成功构建了Mo、Fe、Co、Mo和Go-Mo二元硫化物簇。通过x射线吸收光谱和FEFF代码确定了团簇的结构。随着乙醇的氧化作用，活性随着氧化Mo团簇尺寸的增大而增大。结果表明，Fe_6Ox团簇在沸石的钠笼中形成，并表现出较高的NOx减排活性。结果表明，在分子筛笼中产生了具有硫代立方烷结构的Co1Mo_2S_6簇。结果表明，Co-Mo二元硫化物簇是工业上最重要的加氢处理催化剂活性位点的良好模型。