摘要
利用Li+／MgO催化剂上乙烷氧化脱氢制乙烯及IR、TPD等测试手段对外[Li+O-]中心的形成机理及其性质进行了研究，表明［Li+O－］中心最初生成与MgO表面的自由羟基相关，气相氧、反应温度配位数等对生成[Li＋O－]有一定程度的影响．
In this paper, the formation mechanism and characterization of [Li+O-] centers on Li +/MgO are investigated by the reaction of oxidation-dehydrogenation of ethane to ethene. The concentration of the centers increases with disappearance of free hydroxyl groups ln Li+/MgO. The Li+ entering defect of cations reacts with free hydroxyl to form [Li+O-j, for which the mechanism is as follows:They have a positive heat of formation, thus, the concentration of the centers increases with increaslng temperature The process of forming [Li+o-] needs to expend surface oxygen,thus, suitable O2(g) is necessary according to the balance of oxygen species over the catalysts, but excessive O2(g) is harmful. The defect of lower coordination numbers affects the formation of [Li+O-j, because it affects the existent state of surface Li+.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
1997年第3期449-453,共5页
Chemical Journal of Chinese Universities
基金
国家自然科学基金
关键词
固体碱
催化剂
氧化脱氢
锂
氧化镁
活性中心
[Li^+O^-] centers,Solid base catalyst,Oxdiation-dehydrogenation
