Mg-V-O催化剂在环己烷氧化脱氢反应中的双晶相间协同效应

Biphasic Synergistic Effects of Mg-V-O Catalysts in Oxidative Dehydrogenation of Cyclohexane

在机械混合的MgO-Mg3(VO4)2,Mg3(VO4)2-Mg2V2O7和V2O5-MgV2O6双晶相催化剂体系上,研究了晶相间协同催化效应对环己烷氧化脱氢反应性能的影响.催化剂表征和反应结果表明,双晶相间协同效应或源于不同晶相间形成的内聚界面,或遵从溢流氧的遥控机理,或产生于其中一个晶相完全包覆整个催化剂表面.当在Mg3(VO4)2上进行环己烷氧化脱氢反应时,可加入适量MgO或Mg2V2O7以提高其催化性能.在80%Mg3(VO4)2-20%Mg2V2O7催化剂上,当环己烷转化率为15.5%时,环己烯选择性达44.9%.

The biphasic synergistic effect of a mechanically mixed Mg-V-O catalyst system,which included MgO-Mg3（VO4）2,Mg3（VO4）2-Mg2V2O7,and V2O5-MgV2O6 catalysts,in the oxidative dehydrogenation of cyclohexane was studied.Characterization results and catalytic performance measurements reveal that the biphasic synergistic effect derives from three mechanisms：the formation of coherent interface of the two phases,the remote control mechanism originated from the spillover of mobile surface oxygen,and the formation of a surface contamination layer of one phase on the surface of the catalyst.The biphasic synergistic effect on the conversion,yield,and selectivity was observed in Mg3（VO4）2 mixing with a suitable amount of MgO and Mg2V2O7.Among the catalyst system,the 80%Mg3（VO4）2-20%Mg2V2O7 catalyst exhibits better catalytic performance and shows cyclohexene selectivity of 44.9% with cyclohexane conversion of 15.5%.