Comparative studies on the properties of new and conventional perovskite-type LaCoO3

The physical properties and redox chemistry of perovskite-type LaCoO3 prepared by reactive grinding and by the citrate method, have been comparatively studied by temperature-programmed reduction (TPR), X-ray diffraction (XRD). N-2 adsorption-desorption, and infrared spectroscopy (IR). XRD and N-2 adsorption-desorption measurements show that LaCoO3 prepared by reactive grinding possesses a smaller particles size and thus a greater specific surface area. An IR study suggests that there would exist a large amount of oxygen defects in LaCoO3 prepared by reactive grinding. TPR results illustrate that the redfuction of LaCoO3 to Co-0/LaCoO3 requires a higher temperature for a sample prepared by reactive grinding than for the one prepared by the citrate method. Due to a more difficult reduction. LaCoO3 preparedby reactive grinding displays a better stability of the perovskite structure than LaCoO3 prepared by the citrate method under a reducing atmosphere.