摘要
采用恒定pH共沉淀法制备不同Ni/Co摩尔比的3(NixCo1-x)-Al类水滑石前驱体,600℃焙烧得3(NixCo1-x)Al混合氧化物(MMO)催化剂(x=1,0.95,0.90,0.75,0.50,0.25,0),通过电感耦合等离子体发射光谱、N2物理吸附-脱附、X射线衍射和透射电子显微镜表征其组成、表面织构、晶相和微观形貌,考察Ni/Co摩尔比对其丙烷氧化脱氢制丙烯催化性能的影响.结果表明,3(Ni0.90Co0.10)Al MMO催化剂催化性能最佳:丙烯选择性随反应温度升高未发生明显降低,反应温度500℃时丙烷转化率31%、丙烯选择性48%,丙烯收率15%,且催化剂寿命良好.通过X射线光电子能谱、H2程序升温还原和原位电导测试研究发现,掺杂少量Co后催化剂表面Ni(II)与Co(II/III)间存在电子交互作用,表面类NiO相分散性提高,晶格氧物种增多,催化剂具有优良的氧化还原可逆性.
A series of 3(NixCo1-x)-Al layered double hydroxide(LDH)precursors with different Ni/Co molar ratios were prepared by a constant pH coprecipitation method.The 3(NixCo1-x)Al mixed oxide(MMO)catalysts(x=1,0.95,0.90,0.75,0.50,0.25,0)were obtained after calcination of the LDH precursors at 600℃.The composition,surface texture,crystal phase and micromorphology of the catalysts were characterized by Inductively Coupled Plasma Emission Spectroscopy(ICP-MS),N2 Physical Adsorption-desorption,X-ray Diffraction(XRD)and Transmission Electron Microscope(TEM).And the effects of Ni/Co molar ratios on their catalytic performance for oxidative dehydrogenation of propane(ODHP)to propylene were investigated.The results showed that 3(Ni0.90-Co0.10)Al MMO catalyst had the best catalytic performance:The propylene selectivity was not decreased obviously with the increase of reaction temperature;the propane conversion was 31%,the propylene selectivity was 48%and the propylene yield was 15%at 500℃;furthermore the stability of the catalyst was excellent.It was considered that there was an electronic interaction between the surface Ni(II)and Co(II/III),the dispersion of the surface NiO-like phase was improved and the surface lattice oxygen species were increased after a small amount of Co doping,then the catalyst showed an excellent reversibility of oxidation-reduction,through the study of X-ray Photoelectron Spectroscopy(XPS),H2 Temperature Programmed Reduction(H2-TPR)and In-situ conductivity measurements.
作者
高晓霞
王奖
徐爱菊
贾美林
GAO Xiao-xia;WANG Jiang;XU Ai-ju;JIA Mei-lin(College of Chemistry and Environmental Science,Inner Mongolia Key Laboratory of Green Catalysis,Inner Mongolia Normal University,Hohhot 010022,China)
出处
《分子催化》
EI
CAS
CSCD
北大核心
2019年第6期531-541,共11页
Journal of Molecular Catalysis(China)
基金
内蒙古自治区水环境安全协同创新培育中心项目(XTCX003)
内蒙古自然科学基金(2019MS02016)
内蒙古师范大学研究生科研创新基金资助项目(CXJJS18084).
关键词
类水滑石
混合金属氧化物
镍
钴
丙烷氧化脱氢
layered double hydroxide
mixed metal oxide
nickel
cobalt
oxidative dehydrogenation of propane
