TAILIEUCHUNG - Comparative studies on the characteristic properties of the ground and conventional LaCo0.7Cu0.3O3 perovskite
The characteristics of two perovkites and a blend of mixed oxides prepared by reactive grinding and citrate complex method have been comparatively investigated using several techniques (X-ray, BET, H2-TPR, chemisorption, O2-TPD). XRD results confirm the successful substitution of Co by Cu in the lattice of La(Co,Cu)O3 perovkite. The ground materials with smaller particle sizes and larger surface area show more thermal stability than does the citratederived sample under the same reducing conditions. | Journal of Chemistry, Vol. 47 (4), P. 499 - 505, 2009 Comparative studies on the characteristic properties of the ground and conventional perovskite Received 24 April 2008 NGUYEN TIEN THAO1, SERGE KALIAGUINE2 1 Faculty of Chemistry, College of Sciences, Vietnam National University, Hanoi 2 Department of Chemical Engineering, Laval University, Quebec, Canada, G1K 7P4 Abstract The characteristics of two perovkites and a blend of mixed oxides prepared by reactive grinding and citrate complex method have been comparatively investigated using several techniques (X-ray, BET, H2-TPR, chemisorption, O2-TPD). XRD results confirm the successful substitution of Co by Cu in the lattice of La(Co,Cu)O3 perovkite. The ground materials with smaller particle sizes and larger surface area show more thermal stability than does the citratederived sample under the same reducing conditions. Due to a lower surface area and nonporous structure, the conventional sample adsorbed a smaller amount of oxygen on the surface sites and on the vacancies compared with the other catalysts. I - Introduction Perovkites have been of interest in applied fields of both physic and chemistry because of their attractive characteristics including the electric, magnetic, and optical properties. Transition metal-containing perovskite-type oxides have shown potential catalytic applications in both oxidation and reduction reactions [1]. LaCoO3, for example, is one of the typical mixed oxides of this family having a rhombohedral distortion of the cubic perovskite structure which has been an excellent candidate for three-way-catalyst for three decades [1]. Moreover, cobaltate perovskite-type oxides were thoroughly investigated and exploited as catalysts or catalyst precursor for the oxidation of CO and hydrocarbons, NOx decomposition, hydrogenation and hydrogenolysis [2-4]. The deformation or introduction of another transition metal into the perovskite lattice both lead to a significant change .
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