中文摘要：

采用无皂乳液聚合法合成了聚甲基丙烯酸甲酯（PMMA）微球,并以此为模板制备了具有三维有序大孔（3DOM）结构的Mg Fe0.1Al1.9O4尖晶石催化剂,考察了其催化乙苯与CO2氧化脱氢生成苯乙烯反应的性能.采用X射线衍射、扫描电镜、程序升温还原以及57Fe穆斯堡尔谱等方法对催化剂的物理化学性质进行表征.结果表明,3DOM Mg Fe0.1Al1.9O4催化剂具有三维有序大孔结构,其大孔孔径为230 nm,孔壁平均厚度为60 nm,其中大部分Fe物种以同晶取代的方式进入到尖晶石骨架中.该催化剂在乙苯与CO2氧化脱氢反应中表现出良好的催化活性和稳定性.通过与具有相同化学组成的nano Mg Fe0.1Al1.9O4催化剂对比研究发现,3DOM Mg Fe0.1Al1.9O4畅通的孔道结构十分有利于反应积碳前驱物的外扩散,对提高催化剂的稳定性具有重要作用.

英文摘要：

Polymethyl methacrylate （PMMA） microspheres were synthesized using an emulsifier-free emulsion polymerization method. A three-dimensionally ordered macroporous （3DOM） MgFe0.1AI1.9O4 spinel-type oxide catalyst was prepared using the synthesized colloidal crystal templates and evaluated for oxidative dehydrogenation of ethylbenzene with CO2. Several techniques, such as powder X-ray diffraction, scanning electron microscopy, temperature-programed reduction, and 57Fe-MSssbauer spectra, were used to characterize the physicochemical properties of the catalyst. The results indicate that 3DOM MgFe01A1.9O4 has a hexagonal ordered arrangement, with a pore diameter of 230 nm and a shell thickness of 60 nm, and that most of its Fe species are incorporated into the spinel lattice. Compared with a nano MgFe01A1.9O4 the 3DOM MgFe01A1.9O4 catalyst exhibited a much higher catalytic stability and less carbon deposition. A possible explanation for the enhanced catalytic stability of 3DOM MgFe01A1.9O4 catalyst is discussed. The three-dimensionally ordered macroporous structure has a large effect on the diffusion of coke precursors and the stability of the catalyst.