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通过过渡金属M(M=Fe、Co、Ni、Mn和Cu)的晶格取代作用,制备了一系列具有磁铅石结构的六铝酸盐复合金属氧化物催化剂CaMAl11O19-δ,并通过XRD、XPS和TPR等技术对催化剂的结构和性质进行了表征。结果表明,这类物质的还原性和催化活性与六铝酸盐的晶体结构和晶格中过渡金属性质密切相关。其中Ni取代六铝酸盐CaNiAl11O19-δ表现出较高催化活性和稳定性,在780℃反应2h,CH4和CO2转化率分别达93.4%和91.2%,没有发现活性组分烧结和催化剂失活,其它过渡金属取代催化剂活性均低于CaNiAl11O19-δ,过渡金属活性顺序为Ni>>Co>Fe>Mn>Cu。
A series of hexaaluminate composite metal oxide catalysts CaMAl11O19-δ with a magnetoplumbite structure were prepared by lattice substitution of transition metal M (M = Fe, Co, Ni, Mn and Cu) XPS and TPR technology to characterize the structure and properties of the catalyst. The results show that the reducibility and catalytic activity of these materials are closely related to the crystal structure of hexaaluminate and the properties of transition metals in the crystal lattice. Among them, Ni-substituted hexaaluminate CaNiAl11O19-δ showed high catalytic activity and stability. The conversion of CH4 and CO2 reached 93.4% and 91.2% at 780 ℃ for 2h respectively. No sintering of the active component and deactivation of the catalyst were observed, The activities of other transition metal substituted catalysts were lower than that of CaNiAl11O19-δ, and the order of transition metals was Ni> Co> Fe> Mn> Cu.