氧和乙烯在银-钡催化剂上的吸附和反应机理研究  

STUDIES ON THE ADSORPTION AND REACTION MECHANISM OF OXYGEN AND ETHYLENE ON Ag-Ba CATALYSTS

作　　者：唐亮[1] 邓景发[1] 彭寅生 张式 

机构地区：[1]复旦大学化学系,上海200433 [2]上海石油化工研究所,上海200137

出　　处：《Chinese Journal of Catalysis》1991年第4期251-254,共4页催化学报（英文）

基　　金：国家教委博士点专项基金

摘　　要：在超高真空条件下用热脱附和功函数变化等方法研究了氧在银-钡催化剂上的吸附和反应。结果表明,氧在银-钡上存在三种吸附态,用CO滴定反应证实了α和β态是表面原子态吸附,而γ态是体相原子态。乙烯在清洁表面上不吸附,但在预吸附氧的表面上发生吸附。程序升温反应谱的结果表明,氧和乙烯在银-钡表面上发生两种反应,一种是乙烯直接与BaO上的氧发生燃烧反应,另一种则是乙烯与吸附在银上的氧发生反应生成稳定中间体,此中间体部分脱附成环氧乙烷,而另外部分深度氧化为二氧化碳和水。Under ultra high vacuum condition, the adsorption of oxygen and ethylene on electrolytic silver containing barium was studied by mass spectroscopy and work function change measurement. The results indicate that there are three adsorption states of oxygen on Ag-Ba surface. a and B states are atomic adsorption, y is a subsurface state as evidenced by CO neutralization reaction. Ethylene doesn't adsorb on clean surface, but it adsorbs on silver surface pre-adsorbed with oxygen. TPRS results indicate that ethylene reacts with oxygen on silver surface via two paths, one is that the adsorbed oxygen on Ba reacts directly with ethylene to combustion, the other is that the oxygen adsorbed on silver reacts with ethylene to form an intermediate,a part of the intermediate is desorbed, another part reacts with adsorbed oxygen to combustion. The results of activity and selectivity of Ag-Ba catalyst can be explained by this mechanism.

关 键 词：乙烯 环氧化 银-钡催化剂 氧 吸附 

分 类 号：O623.121[理学—有机化学]