钙钛矿型氧化物LaMO_3的导电性与其CO_2甲烷化活性

CO_2 Methanation Activity and Conductivity of Perovskite—type Oxides LaMO_3

用柠檬酸络合法制得系列化合物LaMO_3(M=Mn,Fe,Co,Ni),经X—射线衍射(XRD)鉴定均为单一钙钛矿型氧化物。LaFeO_3属于正交晶型;LaMnO_3,LaCoO_3和LaNiO_3属三方晶型。测定表明CO_2甲烷化反应活性顺序为:LaNiO_3>LaCoO_3>LaMnO_3>LaFeO_3,与其导电性大小顺序相一致。LaMO_3的导电性与过渡金属离子M的d电子离域性质有关。

A series of LaMO_3(M=Mn, Fe, Co and Ni) catalysts have been synthesized by citric acid comlexing method. X-Ray Diffraction.(XRD) spectra indicate that these compounds are single perovskite in structure. La-FeO_3 belongs to rhombic system, the others belong to trigonal system, The activity order for catalysing CO_2 methanation is LaNiO_3>LaCoO_3LaMnO_3>LaFeO_3, which corresponds to that of their conductivities, The conductivity for LaMO_3 depends to its delocalized dcgree of d electrons in transition metal ions