CO在钙钛矿型稀土氧化物LaMO_3(M=Cr,Mn,Fe,Co,Ni)上的氧化反应

Oxidation of CO over Perovskite-type Rare-earth Oxides LaMO_3 (M=Cr, Mn, Fe, Co, Ni)

本文用柠檬酸络合法制取了比表面为18.3～31.2m^2/g的LaMO_3(M-Cr,Mn,Fe,Co,Ni)系列化合物。X射线衍射(XRD)鉴定均为单一相钙钛矿型氧化物。LaCrO_3与LaFeO_3物属于正交晶型;LaMnO_3,LaCoO_3和LaNiO_3属三方晶型。在反应温度低于300℃时,一氧化碳氧化反应催化活性次序为:LaMnO_3>LaCoO_3>LaNiO_3>LaFeO_3>LaCrO_3,呈现出LaMO_3晶格氧化合能愈低,催化活性愈好的规律。

A series of LaMO_3 (M=Cr, Mn, Fe, Co, Ni) catalysis with larger specific surface have been synthesized by citric acid complexing method. X—Ray Diffraction(XRD) spectra indicate that these compounds are single perovskite in structure. LaCrO_3 and LaFeO_3 belong to rhombic system, the others belong to trigonal system. Below 300 C, the catalytic activities for CO oxidation of LaMO_3(M=Cr, Mn, Fe, Co, Ni)have been dete(■)ed and have following order: LaMnO_3>LaCoO_3>LaNiO_3>LaFeO_3>LaCrO_3. It secms that the activity increase with the decreasing of the binding cpergy of the oxgyen in LaMO_3 (M=Cr, Mn, Fe, Co, Ni).