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

 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%.

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

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 con-tamination layer of one phase on the surface of the catalyst. The biphasic synergistic effect on the conversion, yield, and selectivity was ob-served 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%.