Synthesis of perovsite-type oxide catalysts, Ln(Fe, Co)O3 (Ln=La, Pr, Sm, Gd, Dy, Ho, Er, and Yb), from the thermal decomposition of the corresponding cyano complexes

The influence of A-site lanthanoids in the perovskite-type oxide catalysts, LnFexCo1−xO3 (Ln = La, Pr, Sm, Gd, Dy, Ho, Er, and Yb), prepared by the thermal decomposition of cyano complexes, Ln[FexCo1−x(CN)6]·nH2O, on the catalytic activity of CO oxidation was investigated. Using XRD, N2 adsorption, SEM, XPS, and H2-temperature programmed reduction (TPR) techniques, it was found that A-site lanthanoid ions in perovskite-type oxide LnFeO3 affect the formation temperature of single phase, the crystalline structure, and the size of perovskite-type oxide particles. The catalytic activity of LnCoO3 was improved by the replacement of Co ion with Fe ion regardless of the kind of A-site lanthanoid ion. A-site lanthanoids in perovskite-type oxide also affect the reducibility of B-site Co ion in LnFe0.5Co0.5O3, leading to the change in the catalytic property. TPR results of LnFe0.5Co0.5O3 suggest that the reducibility of Co ion is related to the distortion of perovskite structure.