三维有序介孔结构氧化钼制备及催化性能

以三维有序介孔分子筛KIT-6为模板剂制备碳模板, 七钼酸铵为钼源, 采用超声辅助下的真空浸渍法, 合成了三维(3D)有序介孔、蠕虫状介孔MoO₃。采用TEM、HRTEM、SAED、XRD、TG/DT、N₂吸脱附等对材料物理性能进行了表征。采用H₂-TPR、甲苯和一氧化碳完全氧化等对催化性能进行了评价。研究发现: 制备的三维有序介孔MoO₃为正交相晶体结构, 比表面积194 m²/g; 在转化率分别为50%、90%、100%时, 甲苯的起燃温度分别为203℃、215℃、225℃; CO起燃温度分别为114℃、158℃、180℃。3D-MoO₃优良的催化性能与高比表面和三维有序介孔架构密切相关。

Fabrication and Excellent Catalytic Performance of Three-dimensional Ordered Mesoporous Molybdenum Oxides

Three-dimensional (3D) ordered and wormhole-like MoO₃ mesoporous structures were synthesized based on ultrasound-assisted vacuum impregnation method. Carbon template was used in the synthesis process, which was prepared by using mesoporous molecular sieve KIT-6. Hexaammonium molybdate acted as molybdenum source. The as-prepared MoO₃ samples were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), thermogravimetric analysis/differenctial scanning calorimetry (TG/DSC), and N₂ adsorption-desorption measurement. The catalytic performance of MoO₃ mesoporous structure was evaluated by hydrogen temperature-programmed reduction (H2-TPR), and complete oxidation of toluene and carbon monoxide (CO). It was found that the initiation temperatures of toluene were 203℃, 215℃ and 225℃, respectively, and the initiation temperatures of CO were 114℃, 158℃ and 180℃, respectively, with their conversion rates of 50%, 90% and 100%, respectively. The well catalytic performance was attributed to 3D ordered mesoporous structure and high surface area of as-obtained MoO₃ materials.