摘要
通过微乳凝胶法制备的一系列不同MoO_3质量分数(4%～16%)的MoO_3/SiO_2纳米复合催化剂,由差示扫描量热一热重分析确定催化剂前驱体的焙烧温度,分析了MoO_3在SiO_2表面的阈值;运用透射电镜、X射线衍射和Fourier转换红外分析等方法对其结构、形貌以及催化剂表层氧化钼与氧化硅之间的相互作用进行了结构表征;并以环己烷催化脱氢制备环己烯为目标反应,对催化剂进行了活性测试。结果表明:在该实验条件下所制备的复合催化剂中,MoO_3在SiO_2上的单层分散阈值在12%～14%之间:同时,MoO_3通过Mo—O—Si化学键而牢固结合在SiO_2表面。经催化活性测试后发现:催化剂中MoO_3含量在阈值水平附近时,其催化活性最优。
A series of molybdic oxide/silica nanostructure complex catalyst were prepared by microemulsion-gel method. The amounts of molybdenum oxides varied between 4% and 16% （mass fraction, the same below）. Using differential scanning calorimetry-thermogravimetry, the thermal treatment temperature of complex catalyst precursors and molybdic oxide threshold on the surface of silica were obtained. The crystal structure, the appearance of the nanocatalysts and interaction between molybdic oxide and silica on the surface of the nanocatalyst were characterized by powder X-ray diffraction, transmission electron microscopy and Fourier transform-infrared spectroscopy. The catalytic properties were studied to acquire cyclohexene from cyclohexane. The analytic results show that the molybdic oxide content threshold value of nanocatalysts prepared by the microemulsion-gel method is between 12% and 14%, and there are interactions between molybdic oxide and silica with the band of Mo-O-Si. The results of catalytic activity tests indicate that when the content of MoO3 in the complex catalyst is quite close to the threshold value, the catalytic performance of the nanocatalyst is optimum.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2007年第11期1473-1477,共5页
Journal of The Chinese Ceramic Society
基金
湖南省自然科学基金(06JJ4009)资助项目。
关键词
氧化钼/二氧化硅
微乳-凝胶法
环己烷脱氢
表面结构
多相催化
molybdic oxide/silica
microemulsion-gel method
cyclohexane dehydrogenation
surface structure
heterogeneous catalysis
作者简介
詹拥共（1973-），男，讲师。
通讯作者：蔡炳新（1956-），男，教授。
