Journal of Physical Chemistry B, Vol.110, No.51, 25782-25790, 2006
Synthesis and characterization of mesoporous ceria with hierarchical nanoarchitecture controlled by amino acids
In this work, we report the synthesis and characterization of mesoporous ceria with hierarchical nanoarchitectures controlled by amino acids. During the synthesis procedure, cerium oxalate precipitate was treated hydrothermally with different amino acids as crystallization modifiers, and hierarchically structured cerium oxalate precursors were obtained. Ceria can be produced after thermal decomposition of the cerium oxalate precursors. Structure and properties of the product were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, N-2 adsorption analysis, and X-ray photoelectron spectroscopy (XPS) methods. The results indicate that the mesoporous ceria with hierarchical nanoarchitectures are composed of nanosized ceria crystallites as building units and possess high surface area and high concentration of oxygen vacancy. Depending on different amino acids as the crystallization modifiers, the ceria exhibit different morphologies, such as dendritic aggregation of rods, dumbbells of nanorod arrays, or aggregated spheres. It is proposed that both the type of functional side groups and the length of the side groups of the amino acids influence the morphologies of the ceria. Meanwhile, the solvent and hydrothermal treatment temperatures also play important roles in the morphological control. The method reported in this work would be regarded as a general way to fabricate mesoporous metal oxides with hierarchical nanoarchitectures.