Fabrication of three dimensional CeO2 hierarchical structures: Precursor template synthesis, formation mechanism and properties
Fabrication of three dimensional CeO2 hierarchical structures: Precursor template synthesis, formation mechanism and properties
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DOI：
10.1039/c0ce00635a
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发表时间：
2011-04
期刊：
影响因子：
3.1
通讯作者：
Jingjing Wei;Zhijie Yang;Yanzhao Yang
中科院分区：
文献类型：
--
作者：
Jingjing Wei;Zhijie Yang;Yanzhao Yang
本文通过溶剂热法制备的甲酸铈前驱体的热分解合成了三维介孔CeO2分级结构。应用 X 射线衍射 (XRD)、场发射扫描电子显微镜 (FE-SEM)、透射电子显微镜 (TEM)、傅里叶变换红外 (FT-IR) 和热重分析 (TG) 来表征前驱体。分别使用二甲基亚砜（DMSO）和氨溶液（1 M）作为溶剂和碱源制备海胆状Ce（HCOO）3前驱体，而分别使用二甲基甲酰胺（DMF）和NH4HCO3作为溶剂和碱源制备珊瑚状Ce（HCOO）3前驱体。提出了分级结构前驱体的形成机制，涉及各向异性生长-H2O诱导自组装-定向聚集和分解-奥斯特瓦尔德熟化过程。 CeO2分级结构是通过将相应的Ce(HCOO)3前驱体在400℃下退火60分钟获得的。 N2 吸附-解吸等温线表明，源自 Ce(HCOO)3 前驱体的 CeO2 分级结构均表现出大表面积和高孔体积。此外，所制备的具有多级结构的CeO2催化剂对于CO转化为CO2具有很高的活性。
In this paper, three dimensional mesoporous CeO2 hierarchical structures were synthesized through the thermal decomposition of cerium formate precursors, which were prepared by a solvothermal method. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR), and Thermal gravimetric (TG) was applied to characterize the precursors. Urchin-like Ce(HCOO)3 precursors were prepared using dimethyl sulfoxide (DMSO) and ammonia solution (1 M) as solvent and base source, respectively, while coral-like Ce(HCOO)3 precursors were prepared using dimethyl formamide (DMF) and NH4HCO3 as solvent and base source, respectively. The formation mechanism of the hierarchical structured precursors was proposed involving a process of anisotropic growth–H2O induced self-assembly–oriented aggregation and disassembly–Ostwald ripening. CeO2 hierarchical structures were obtained by annealing the corresponding Ce(HCOO)3 precursors at 400 °C for 60 min. N2 adsorption–desorption isotherms indicate that both CeO2 hierarchical structures derived from their Ce(HCOO)3 precursors display large surface areas and high pore volumes. In addition, the as-prepared CeO2 catalysts with hierarchical structures are highly active for conversion of CO to CO2.