Abstract:

This paper carried out the screening of WO _x /SiO₂ catalyst carrier and the investigation of WO _x loading capacity, and successfully screened a domestic SiO₂ carrier with excellent performance. The structure and properties of the catalyst were characterized by nitrogen physical adsorption, XRD, Raman spectroscopy and TEM/EDS. The dispersion of WO _x species on the carrier was mainly investigated, the catalytic reaction performance of disproportionation of ethylene and butene to propylene was investigated, and the performance was compared with that of a foreign commercial catalyst. The research results show that the WO _x loading threshold of the domestic carrier S?SiO₂ is 8%. At this time, the catalyst shows the best catalytic activity and selectivity. Compared with the catalytic performance of the comparative commercial catalyst, the catalyst activity is nearly 10% higher, and the stability and selectivity are equivalent, and the correlation structure characterization results can confirm that the dispersion characteristics of WO _x species on the support are the key factors that affect the catalytic performance, while the SiO₂ support and loading are both the key to the dispersion state of WO _x species. This study can provide a basis for the localization of WO _x /SiO₂ catalysts for high?efficiency olefin disproportionation reactions, especially the selection of domestic SiO₂ carriers.

Key words: WO _x /SiO₂ catalyst, Carrier, Olefin disproportionation reaction, Loading, Dispersion characteristics

摘要：

通过对WO _x /SiO₂催化剂载体的筛选和WO _x 负载量的考察，成功筛选出一种性能优异的国产SiO₂载体，运用氮气物理吸附、XRD、Raman光谱和TEM/EDS对催化剂结构进行表征，考察了WO _x 物种在载体上的分散情况和乙烯与丁烯歧化制丙烯的催化反应性能，并与国外某商业催化剂的性能进行了对比。结果表明，当国产载体S?SiO₂的WO _x 负载量阈值为8%时，催化剂显示出最佳催化活性和选择性；与商业催化剂的催化性能相比，其催化活性高近10%，且稳定性和选择性相当；关联结构表征结果证实，WO _x 物种在载体上的分散特征是影响催化性能的关键因素，SiO₂载体和负载量也是影响WO _x 物种分散状态的关键。本研究可为高效烯烃歧化反应WO _x /SiO₂催化剂的国产化，尤其是国产SiO₂载体的选择提供依据。

关键词: WO _x /SiO₂催化剂, 载体, 烯烃歧化反应, 负载量, 分散特征