Hydrothermal And Ion-exchange Synthesis Of High-purity Micro/nano-ceo₂

In this paper, different morphology and different partical size of precursors of cerium oxide were synthesized for the first time by low-temperature hydrothermal and ion exchange method. After modulating factors of the ion exchange fiber pre-exchange degrees, the concentration of urea, synthesis temperature and time, cerium oxide precursors with different particle size distribution and nanometer slice and micron stick for feature morphology were obtained. Smaller diameter of cerium oxide precursor can obtain by appropriately reducing pre-exchange degree of ion exchange fiber and moderately increasing reaction temperature; certain particle size of flower shape clusters self-assembly by micron sticks can be obtained under the feature synthesized condition.Additive ion exchange fiber plays the leading role in the formation and growth of rodlike cerium oxide precursor in ion exchange and low-temperature hydrothermal method. The influence of the amount of urea, the ion exchange fiber pre-exchange degrees, synthesis temperature and synthesis time on the morphology and size of product realized by affecting the capacity of diffusion and migration of Ce(OH)2+ and CO32- on the surface of ion exchange fiber.The cerium oxide precursor prepared by ion-exchange and low-temperature hydrothermal is orthorhombic structure mono-crystal Ce2O(CO3)2·H2O, according to the results of TG, abundant cerium oxide consist in cerium oxide precursor, which probable highly dispersed in Ce2O(CO3)2·H2O crystal with no finalize the design condition, after roasting at 400 to 500℃obtained cubic pleomorphic CeO2, well crystallization, and can keep the basic morphological features of precursor.The formation and growth rate of grains prepared by ion-exchange hydrothermal method are related to the pre-exchange degrees, the concentration of urea, the temperature conditions, ion exchange fiber become grain growth template under certain conditions, controlling the nucleation and growth process, realized synthesizing different morphology nanomaterials at the low-temperature dual control; impurity ions of system enriched in fiber through ion exchange reaction and have no need to wash. The whole synthesis process is environment friendly and energy saving, opening a new way for the synthesis of high purity of nanomaterials.