Abstract
$LaMnO_3$ and A site substituted $La_{0.9}Sr_{0.1}MnO_3$(a=$5.33\AA$, c=$13.27\AA$), B site substituted $LaMn_{0.9}Cu_{0.1}O_3$(a=$5.52\AA$, c=$13.31\AA$) mixed oxides were prepared by Citrate sol-gel method. The powder X-ray diffraction patterns of these oxides were indexed with single phase hexagonal perovskite structures. According to the TRR result, oxygen stoichiometry of these oxides were oxidative nonstoichiometry as like $LaMnO_{3.16}$, $La_{0.9}Sr_{0.1}MnO_{3.10}$ and $LaMn_{0.9}Cu_{0.1}O_{3.14}$ Reduction reactions of un-substituted $LaMnO_3$ was two steps, but specific site(A site of B site) partially substituted $LaMnO_3$ oxides were procees to three reactions.
$LaMnO_3$(a=$5.51\AA$, c=$13.33\AA$) 페로브스카이트형 복합산화물에서 A site인 La자리에 Sr을 치환시킨 $La_{0.9}Sr_{0.1}MnO_3$(a=$5.33\AA$, c=$13.27\AA$)와 B site인 Mn을 Cu로 치환시킨 $LaMn_{0.9}Cu_{0.1}O_3$(a=$5.52\AA$, c=$13.31\AA$) 복합산화물을 Citrate sol-gel법을 이용하여 합성하였으며 분말 X-ray회절 분석기(XRD)을 이용하여 Rhombohedral의 페로브스카이트 구조임을 확인하였다. 수소 환원분위기에서의 TRR결과에 의하면 이들 산화물의 산소 화학양론은 $LaMnO_{3.16}$, $La_{0.9}Sr_{0.1}MnO_{3.10}$, $LaMn_{0.9}Cu_{0.1}O_{3.14}$의 조성을 갖는다. $LaMnO_3$는 2단계 환원반응을 일으키지만 각 자리를 치환시킨 $LaMnO_3$ 복합산화물은 3단계 환원반응을 일으켰다.