CAJ | 학술논문

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MgFe0.1Al1.9O4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 MgFe0.1Al1.9O4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 MgFe0.1Al1.9O4催化剂对比研究发现,3DOM MgFe0.1Al1.9O4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.
채용무조유액취합법합성료취갑기병희산갑지(PMMA)미구,병이차위모판제비료구유삼유유서대공(3DOM)결구적MgFe0.1Al1.9O4첨정석최화제,고찰료기최화을분여CO2양화탈경생성분을희반응적성능.채용X사선연사、소묘전경、정서승온환원이급57Fe목사보이보등방법대최화제적물이화학성질진행표정.결과표명,3DOM MgFe0.1Al1.9O4최화제구유삼유유서대공결구,기대공공경위230 nm,공벽평균후도위60 nm,기중대부분Fe물충이동정취대적방식진입도첨정석골가중.해최화제재을분여CO2양화탈경반응중표현출량호적최화활성화은정성.통과여구유상동화학조성적nano MgFe0.1Al1.9O4최화제대비연구발현,3DOM MgFe0.1Al1.9O4창통적공도결구십분유리우반응적탄전구물적외확산,대제고최화제적은정성구유중요작용.
Polymethyl methacrylate (PMMA) microspheres were synthesized using an emulsifier-free emulsion polymerization method. A three-dimensional y ordered macroporous (3DOM) MgFe0.1Al1.9O4 spinel-type oxide catalyst was prepared using the synthesized col oidal 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-M?ssbauer spectra, were used to characterize the physicochemical properties of the catalyst. The results indicate that 3DOM MgFe0.1Al1.9O4 has a hexagonal ordered arrangement, with a pore diameter of 230 nm and a shel thickness of 60 nm, and that most of its Fe species are incorporated into the spinel lattice. Compared with a nano MgFe0.1Al1.9O4, the 3DOM MgFe0.1Al1.9O4 catalyst exhibited a much higher catalytic stability and less carbon deposition. A possible explanation for the enhanced catalytic stability of 3DOM MgFe0.1Al1.9O4 catalyst is discussed. The three-dimensional y ordered macroporous structure has a large effect on the diffusion of coke precursors and the stability of the catalyst.