文献类型：期刊文献

英文题名：Epoxidation of propylene by molecular oxygen over supported Ag-Cu bimetallic catalysts with low Ag loading

作者：Zheng, Xiang[1];Zhang, Qing[1];Guo, Yanglong[1];Zhan, Wangcheng[1];Guo, Yun[1];Wang, Yunsong[1];Lu, Guanzhong[1]

机构：[1]E China Univ Sci & Technol, Key Lab Adv Mat, Res Inst Ind Catalysis, Shanghai 200237, Peoples R China

年份：2012

卷号：357

起止页码：106

外文期刊名：JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL

收录：;EI(收录号：20121214886335);WOS:【SCI-EXPANDED(收录号:WOS:000302664000015)】；

基金：This project was supported by National Basic Research Program of China (2010CB732300) and Commission of Science and Technology of Shanghai Municipality (09JC1404000), Program for New Century Excellent Talents in University (NCET-09-0343), Shu Guang Project of Shanghai Municipal Education Commission and Shanghai Education Development Foundation (10SG30).

语种：英文

外文关键词：Epoxidation of propylene; Propylene oxide; Molecular oxygen; Supported Ag-Cu bimetallic catalyst; Surfactant-protected colloidal method

摘要：Supported Ag-based bimetallic catalysts with low Ag loading of 3.0 wt%, prepared by the surfactant-protected colloidal method, were investigated for the epoxidation of propylene by molecular oxygen and characterized by UV-vis, XRD, TEM, XPS, and H-2-TPR. Ag-Cu/BaCO3 bimetallic catalyst exhibits better catalytic performance, governed by the molar ratio of Ag/Cu, than other supported Ag-based bimetallic catalysts and monometallic catalysts for the epoxidation of propylene by molecular oxygen. The highest propylene oxide selectivity of 55.1% and the propylene conversion of 3.6% were achieved over Ag-95-Cu-5/BaCO3 bimetallic catalyst. XRD and TEM results show that a small quantity of Cu can effectively regulate the size of Ag crystallites to restrain their agglomeration. XPS results indicate that the presence of Cu can withdraw electrons from nearby Ag and thus make Ag electropositive, which is beneficial to produce more active sites where electrophilic oxygen species can be absorbed to increase the propylene oxide selectivity. H-2-TPR results show that the reactivity and the amount of the oxygen species adsorbed on Ag surface can be regulated by the synergistic effect between Ag and Cu, which plays an important role in increasing the propylene oxide selectivity and the propylene conversion. (C) 2012 Elsevier B.V. All rights reserved.