Effects of oxide supports on ethylene epoxidation activity over Ag-based catalysts

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• 作者：Atiporn Chongterdtoonskul^a ; Johannes W. Schwank^c ; Sumaeth Chavadej^a ; ^b ; ^{sumaeth.c@chula.ac.th}
• 关键词：Ethylene epoxidation ; SrTiO3 ; Sol&ndash ; gel ; 伪-Alumina ; Ag
• 刊名：Journal of Molecular Catalysis A ; Chemical
• 出版年：2012
• 期刊代码：57_13811169
• 类别：ch
• 出版时间：June, 2012
• 卷：358
• 期：Complete
• 页码：58-66
• 文件大小：1905 K

摘要

In this study, Ag-based catalysts with different loadings on various oxide supports, including low-surface-area 伪-Al₂O₃, Al₂O₃ C, Al₂O_3,Acid, SiO₂ 90, TiO₂ and SrTiO₃ synthesized by a sol-gel process, were investigated for ethylene epoxidation over a range of reaction temperatures. The specific surface area, crystallinity, surface morphology, oxidation state, metal crystallite size, and oxygen and ethylene adsorption characteristics of all prepared catalysts were characterized and correlated to the ethylene epoxidation activity. Compared with conventional Ag catalysts supported on low-surface-area 伪-Al₂O₃, the 17.16 wt%Ag/SrTiO₃ catalyst exhibited much better catalytic activity for the ethylene epoxidation reaction, providing both the highest EO yield of 4.5%and EO selectivity up to 99%. The results indicate that high oxygen and ethylene uptakes, together with the large size of Ag particles, play an important role in achieving the best catalytic activity of the Ag/SrTiO₃ catalyst towards ethylene epoxidation reaction.