氧化铈纳米粒子的制备ppt课件

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XRD of CeO2 synthesized at 600℃、700℃
SEM photo of precursor(a)
Precipitant: ammonia or NH4HCO3 Surface active agent: PEG-4000 Process: nitrate and PEG-4000
were dissolved in distilled wate.Then ammonia or NH4HCO3 solution was added dropwise under vigorous stirring till the pH reached 9. The precipitate was filtered, washed thrice with distilled water and alcohol and dried at 80℃ over night.
LS of CeO2 calcined at 600℃
(a) Ce(NO3)3 + urea, without PEG-4000 (b) Ce(NO3)3 + urea + PEG-4000 (c) (NH4)2Ce(NO3)6 + urea + PEG-4000
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CeO2 Slurry
氧化铈抛光粉
氧化铈抛光轮
玻璃脱色剂氧化铈
大颗粒氧化铈磨料 氧化铈抛光粉/液晶显示屏
此外， CeO2还用作催化材料、高温氧敏材料、 pH传感材料、电化学池中膜反 应器材料、燃料电池的中间材料、中温固体氧化物燃料电池(SOFC)用电极材料4
Synthesis of CeO2
1. Direct precipitation
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XRD of CeO2 synthesized at 700℃
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SEM photoes of CeO2 calcined at 600℃
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Microwave homogeneous precipitation
Nitrate: Ce(NO3)3 or (NH4)2Ce(NO3)6 Precipitant: urea Surface active agent: PEG-4000
Microwave reaction equipment
CO(NH2)2 + H2O → CO2 + 2NH3 NH3 + H2O → NH4+ + OHCO2 + H2O → CO32- + 2H+
水解生成的构晶 离子OH-、CO32-, 在微波辐照作用 下,与Ce3+、Ce4+ 等结合生成不溶 前驱物
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Results and discussion
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SEM photoes of precursor
(a): Ce(NO3)3 + NH3·H2O (b): (NH4)2Ce(NO3)6 + NH3·H2O (c): Ce(NO3)3 + NH4HCO3 (d): (NH4)2Ce(NO3)6 + NH4HCO3
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Biblioteka Baidu
1.Simply introduce the structure and applications of CeO2
2. Synthesis of nanocrystalline CeO2 by different methods
3. Future works
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Brief introduction
Ce3+ or Ce4+
precipitant
precipitation
Stir and ageing stage
Scouring and drying
to calcine precursor
The power of CeO2
technology of direct precipitation
Nitrate: Ce(NO3)3 or (NH4)2Ce(NO3)6
值得注意的是，即使从晶格上失去相当数量 的氧，形成大量氧空位之后，CeO2仍然能保持萤 石型晶体结构，这种亚稳氧化物暴露于氧化环境 时又易被氧化为CeO2，因而CeO2具有优越的储存 和释放氧功能及氧化还原反应能力，同时CeO2也 有着良好的化学稳定性和高温快速氧空位扩散能 力。
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Applications of CeO2
1. Structure of CeO2
CeO2属于萤石型氧化物。 CeO2晶胞中的Ce4+按面心 立方点阵排列，O2-占据所 有的四面体位置，每个Ce4+ 被8个O2-包围，而每个O2则与4个Ce4+配位。
2.功能特性
CeO2的结构中有1/2立方体空隙，可称之为敞 型结构。敞型结构允许离子快速扩散。经高温(T ＞950℃)还原后，CeO2转化为具有氧空位、非化 学计量比的CeO2-X氧化物(0<x<0.5)，而在低温下 (T＜450℃) CeO2可形成一系列组成各异的化合物。
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XRD of precursor 6
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XRD of CeO2 synthesized at 600℃
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XRD of CeO2 synthesized at 500℃
Members: Xianhong Rui Yu Chen Litao Yan Huamin Yao Liangjun Yi
Department of Materials Science and Engineering University of Science and Technology of China Jan 3, 2008
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Results and discussion
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Mean:
(a)0.093um
(b)0.171um
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(c)0.210um
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XRD
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XRD of2precursor (a)