Research And Study Of Laco Catalysts Materials Prepared By Coprecipitation-Spray Method

In this paper, the LaCoO₃ and a series of La_1-xCe_xCoO₃ (x=0.1, 0.2, 0.3, 0.5, 0.7, 0.9),LaCo_1-yCr_yO₃(y=0.1, 0.2, 0.3, 0.4, 0.5) were prepared by co-precipitation spray method. The appearance and structure of these catalysts were analyzed by BET-specific surface area, XRD, TEM, TPR .etc. The catalytic activity for CH₄ of these catalysts were measured and studied. And the thermal-stability was discussed in brief.Drying method of catalyst is an important factor in catalyst preparation process. Spray drying method is in common use in thin grain catalysts preparation. The method could decrease the form-temperature of catalyst, increase the specific surface area of catalyst, and decrease the granularity of catalyst. In this paper, the influences of different preparation conditions on the specific surface area and catalytic activity of catalyst. The best preparation condition was confirmed. The structure and performances of catalysts with different adulterate rate prepared by co-precipitation spray Method were studied and the best adulterate rate was confirmed. The influence of catalytic activity and thermal-stability of different A B site adulteration was studied. It's reported that the form-temperature will decrease 100℃by instead common oven drying method with spray drying method. The proportion of precipitator, aging time, conditions of spray-drying and baking time and temperature would influence the preparation of catalyst more or less. The catalyst with adulteration rate of x=0.3 and y=0.1 has best catalytic activity. The structure and catalytic activity of catalyst with different adulteration changed. The catalytic activity of catalyst with A site adulteration of Ce prepared by spray-drying increased, and the start-burning temperature of the catalyst decreased to 391. 6℃; The start-burning temperature of the catalyst with A site adulteration of Cr was higher, however, the translation rate of catalyst rises quickly as the temperature reach to 500℃, and the catalyst display a prefer catalytic activity after baking 2 hours at 1200℃. The result proved that the LaCoO₃ adulterated with Cr has excellent thermal-stability.