科研之友
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摘要
Manipulation and control of crystal shape and investigation on the fundamental mechanism of cerium carbonate crystallization are the prerequisite of obtaining ceria crystal with targeted morphology.In this work cerium carbonate crystals with varied branching morphology were prepared by controlling the crystallization process without adding any templates. Process analysis technology was applied to reactive crystallization of cerium carbonate to explore the crystallization mechanism. It revealed that the branching morphology of these microcrystals has a strong dependence on the reaction conditions, especially the reaction temperature, sodium bicarbonate solution concentration and feed rate.The pH and turbidity during the reaction crystallization process were monitored by a pH meter and a turbidity meter respectively. An on-line imaging probe was also utilized to monitor the evolution of particle morphology during reactive crystallization. Samples were taken at different times during crystallization and analyzed by X-ray powder diffraction and scanning electron microscope. The data revealed that the crystallization pathway of cerium carbonate is amorphous precursors nucleation-dissolution-recrystallization.The transformation process leads to the formation of cerium carbonate crystal with different branching morphologies.
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