CAJ | 학술논문

以非离子型三嵌段共聚物作为模板剂,异丙醇铝为氧化铝的前驱物,采用一锅法合成了一系列介孔氧化铝负载镍氧化物、钴氧化物以及镍-钴双金属氧化物催化剂,并以介孔氧化铝为载体,采用浸渍法制备了负载Ni-Co氧化物催化剂.采用N2吸附-脱附、高分辨透射电镜(HRTEM)、X射线粉末衍射(XRD)、H2程序升温还原(H2-TPR)以及激光拉曼光谱(LRS)等技术对催化剂的结构与性质进行表征,并考察了催化剂的丙烷氧化脱氢反应性能.结果表明:一锅法制备的各催化剂均有大的比表面积和规整的孔道结构,且负载的金属氧化物高度分散;而浸渍法制备的催化剂,其载体的介孔结构被破坏并有Co3O4晶相生成.在考察的催化剂中,一锅法合成的介孔氧化铝负载Ni-Co氧化物催化剂表现出最佳的丙烷氧化脱氢性能.在450℃、C3H8∶O2∶N2的摩尔比为1∶1∶4和空速(GHSV)为10000 mL·g-1·h-1条件下,该催化剂上丙烯产率为10.3％,远高于浸渍法制备的催化剂上所获得的丙烯产率(2.4％).关联催化剂表征和反应结果,讨论了催化剂结构与性能之间的关系.
이비리자형삼감단공취물작위모판제,이병순려위양화려적전구물,채용일과법합성료일계렬개공양화려부재얼양화물、고양화물이급얼-고쌍금속양화물최화제,병이개공양화려위재체,채용침지법제비료부재Ni-Co양화물최화제.채용N2흡부-탈부、고분변투사전경(HRTEM)、X사선분말연사(XRD)、H2정서승온환원(H2-TPR)이급격광랍만광보(LRS)등기술대최화제적결구여성질진행표정,병고찰료최화제적병완양화탈경반응성능.결과표명:일과법제비적각최화제균유대적비표면적화규정적공도결구,차부재적금속양화물고도분산;이침지법제비적최화제,기재체적개공결구피파배병유Co3O4정상생성.재고찰적최화제중,일과법합성적개공양화려부재Ni-Co양화물최화제표현출최가적병완양화탈경성능.재450℃、C3H8∶O2∶N2적마이비위1∶1∶4화공속(GHSV)위10000 mL·g-1·h-1조건하,해최화제상병희산솔위10.3％,원고우침지법제비적최화제상소획득적병희산솔(2.4％).관련최화제표정화반응결과,토론료최화제결구여성능지간적관계.
A series of mesoporous alumina supported nickel oxide,cobalt oxide,and bimetallic nickelcobalt oxide catalysts were synthesized by a one-pot method,using nonionic triblock copolymer as a template and aluminum isopropoxide as the source of aluminum.For comparison,an additional supported Ni-Co oxide catalyst was prepared by impregnation,using mesoporous alumina as the support.The catalysts were tested for the oxidative dehydrogenation of propane,and their structure and properties were characterized by N2 adsorption-desorption,high-resolution transmission electron microscopy (HRTEM),powderX-ray diffraction (XRD),temperature-programmed H2 reduction (H2-TPR),and laser Raman spectroscopy (LRS).All samples synthesized by the one-pot method had large surface area,highly ordered mesoporous structure,and highly dispersed supported oxide species.However,in the sample prepared by impregnation,the mesostructure of the carrier was destroyed with the formation of Co3O4 phase.Among the catalysts studied,the mesoporous alumina supported Ni-Co oxide catalyst from one-pot synthesis showed the best catalytic performance for propane oxidation to propylene.On this catalyst a 10.3％ propylene yield was obtained at 450 ℃,C3H8∶O2∶N2 molar ratio of 1∶1∶4,and gas hourly space velocity (GHSV) of 10000 mL· h-1.g-1.This result was much higher than the yield of 2.4％ obtained from the catalyst prepared by impregnation.Combining the results of characterization and catalytic reaction,the relationship between structure and performance of the catalysts was discussed.The large difference observed in catalytic performance between catalysts prepared by one-pot and impregnation methods was attributed to their different structures,including textural structure,and dispersion of the supported metal oxide species.