Combustion synthesis of fine-particle ceria

Fine-particle ceria having narrow size distribution is of interest as polishing material for ophthalmological lenses, television tubes, plates and mirrors [1]. The preparation has been reported of such ceria by the hydrolysis of cerium isopropoxide [2] and cerium nitrate [3, 4] followed by thermal decomposition, as well as by the thermal decomposition of cerium oxalate hydrazinate [5] and cerium hydrazine carboxylate [6]. In this letter we report the preparation of fine-particle, large-surface-area ceria by the combustion process developed for the preparation of $\alpha$-alumina [7], aluminates [8], chromites [9] and ferrites [10]. The process involves rapid decomposition of a saturated aqueous solution containing ceric ammonium nitrate and urea $(CH_4N_20)$, carbohydrazide $(CH_6N_4O (CH))$, oxalyl dihydrazide $(C_2H_{16}N_4O_2 (ODH))$ or tetraformal trisazine $(C_4H_{16}N_6O_2 (TFTA))$ redox mixtures