Citrate sol-gel법을 이용하여 perovskite형 복합산화물 LaBO$_3$(B = Mn, Fe, Co)을 공기 중 $850^{circ}C$에서 24시간 동안 소성하여 제조하였다. X-선 회절분석(XRD)과 TPR결과에 의하면 이들 산화물의 결정구조와 산소화학양론은 LaMnO$_{3.16}$(a = 5.507, c = 13.329 $AA$, hexagonal), LaFeO$_{3.17}$(a = 5.554, b = 5.555, c = 7.863 $AA$, orthorhomibic), LaCoO$_{3.0}$(a = 5.436, c = 13.095 $AA$, hexagonal)으로 수소 분위기(300torr)에서의 TPR결과에 의하면 이들 산화물은 2단계 환원반응으로 반응이 진행되며, 열적안정성은 LaMnO$_3$ > LaFeO$_3$ > LaCoO$_3$순으로 나타났고, 반응속도론적 결과 역시 LaCoO$_3$의 활성화에너지 값이 가장 낮음을 보였다.
Perovskite-type mixed oxides LaBO$_3$(B = Mn, Fe, Co) were prepared by citrate sol-gel method in $air(850^{circ}C$, 24h). The oxygen stoichiometries and structures of these oxides were determined by XRD and TPR results as followings; LaMnO$_{3.16}$(a = 5.507, c = 13.329 $AA$, hexagonal), LaFeO$_{3.17}$(a = 5.554, b = 5.555, c = 7.863 $AA$, orthorhomibic), LaCoO$_{3.0}$(a = 5.436, c = 13.095 $AA$, hexagonal). The temperature programmed reduction(TPR) experiments in static 300 torr H$_2$ atmosphere shows that the reduction reaction of LaBO$_3$(B = Mn, Fe, Co) proceeds into two stages, and thermal stabilities of these oxides decreased in the order of LaMnO$_3$ > LaFeO$_3$ > LaCoO$_3$. According to the kinetic analysis the lowest activation energy was obtained for LaCoO$_3$.
