Au／TS-1@Mesosilica双功能催化材料的制备及其催化丙烯直接环氧化性能

Synthesis of bifunctional catalyst Au/TS-1@Mesosilica and applied for direct propylene epoxidation with H_2 and O_2

设计制备了一种新型微孔介孔复合核壳结构钛硅分子筛TS-1@Mesosilica(TS-1@MS),核为MFI结构钛硅分子筛TS-1,壳层为以非离子表面活性剂P123为模板剂组装形成的介孔氧化硅.壳层氧化硅具有三维蠕虫状孔道结构,有利于微孔和介孔部分的连通及反应物和产物的扩散.通过沉积沉淀法将金纳米粒子负载在壳层介孔孔道,和TS-1中的钛活性中心协同,形成适合于C3H6和H2、O2直接气相环氧化制备环氧丙烷(PO)的双功能催化材料.实验结果表明,Au/TS-1@MS在空速8000 mL g 1h 1、温度473 K条件下连续反应132 h,活性和选择性没有明显下降,丙烯转化率保持在3.7%左右,PO选择性87%以上.

A new microporous and mesoporous composite with a core/shell structure, TS-1 @Mesosilica （TS-1@MS）, was synthesized by self-assembly technique. With the assistance of nonionic surfactant as template, the silica shell was readily coated on the surface TS-1 crystal core. Possessing a three-dimensional and interconnected wormhole-like mesopore structure, the silica shell served as a good support for incorporating gold nanoparticles （Au NPs） inside channels, leading a bifunctional catalyst which catalyzes actively and selectively the gas-phase epoxidation of propylene with H2 and O2. Au/TS-l@MS showed a constant propylene conversion （3.7%） and PO selectivity high as 87% at 473 K for 132 h of time on stream, indicating a high stability because of the confining effect of mesopores on Au NPs.