中文摘要：

采用纳米组装法制备了一系列不同Ti含量的具有微孔-介孔复合结构（hybrid）的钛硅分子筛Ti-MCM-41（H）载体,继而用沉积-沉淀法制得纳米金催化剂.通过粉末X射线衍射（XRD）、氮气等温吸附-脱附、傅里叶变换红外（FT-IR）光谱、紫外-可见漫反射（DRUV-Vis）光谱、透射电镜（TEM）及等离子体原子发射光谱法（ICP-AES）对催化剂进行了表征,并考察了纳米金催化剂在氢气/氧气共存条件下丙烯气相直接氧化制环氧丙烷反应中的催化性能.结果表明：合成的微孔-介孔复合结构的钛硅分子筛Ti-MCM-41（H）具有典型的MCM-41结构,Ti（IV）以高分散的形式存在于分子筛的骨架结构中.在常压、423K反应温度下,以Ti/Si摩尔比为1%的Ti-MCM-41（H）为载体制备纳米金催化剂表现出了最佳的催化性能,反应30min,丙烯的转化率达5.4%,环氧丙烷的选择性为74.2%,环氧丙烷的生成速率为73.1g·h-1·kg-1;反应330min后,丙烯的转化率为4.9%,环氧丙烷的选择性为67.3%.

英文摘要：

Microporous-mesoporous hybrid Ti-MCM-41（H） was successfully synthesized by the nano-cluster assembling method.Gold nano-particles were prepared by the deposition-precipitation method.The samples were characterized by powder X-ray diffraction（XRD）,nitrogen isothermal adsorption-desorption,Fourier transform infrared（FT-IR） spectroscopy,diffuse reflectance UV-Vis（DR UV-Vis） spectroscopy,transmission electron microscopy（TEM） and inductively coupled plasma emission spectrometry（ICP-AES）.The catalytic performance of the gold nano-particles was evaluated by the direct gas phase epoxidation of propylene using hydrogen and oxygen.Results revealed that the Ti-MCM-41（H） had a typical mesoporous MCM-41 structure.The results also suggested that isolated Ti（IV） was introduced into the siliceous framework of the support material.Superior catalytic performance was obtained with the gold catalyst supported on Ti-MCM-41（H） in which the Ti/Si molar ratio was 1%.Propylene conversion reached 5.4% at the initial 30 min with 74.2% propylene oxide（PO） selectivity and produced rate 73.1 g·h-1·kg-1.The conversion and PO selectivity were 4.9% and 67.3% after running 330 min on stream at 423 K.