Mesoscale Organization of Nearly Monodisperse Flowerlike Ceria Microspheres

Abstract

Nearly monodisperse flowerlike CeO2 microspheres were synthesized via a simultaneous polymerization-precipitate reaction, metamorphic reconstruction, and mineralization under hydrothermal condition as well as subsequent calcination. The obtained CeO2 microsphere consists of 20-30 nm thick nanosheets as petals. It has an open three-dimensional (3D) porous and hollow structure and possesses high surface area, large pore volume, and marked hydrothermal stability. It can be doped easily after synthesis, and the initial 3D texture is maintained. The controlling factors and a possible formation mechanism are discussed in detail. This novel material can be used as a support for catalysts with various purposes. With CuO loaded on flowerlike CeO2, the catalytic activities and hydrothermal stability of Cu/CeO2 for ethanol stream reforming were examined. At 300 degrees C, the H2 selectivity reached a maximum value of 74.9 mol %, while CO was not detected within the precision of the gas chromatogram. It produced a hydrogen-rich gas mixture in the wide temperature range (300-500 degrees C) and showed excellent hydrothermal stability at high temperature (550 degrees C), which is a good choice for ethanol processors for hydrogen fuel cell applications.

Influence of solvent on the morphology and photocatalytic properties of ZnS decorated CeO2 nanoparticles

“…65,66 Unlike the CeO 2 -EG samples prepared in this study that featured parallel sheets, those obtained nanospheres were composed of sheet-like crystallites oriented in flower petal-like fashions. Other flower-like CeO 2 architectures that consist of nanorods arranged in a spherical morphology, reminiscent of urchin structures, with no sheet-like components, have also been reported.…”

Utilization of Nanoparticles Produced by Aqueous-Solution Methods – Formation of Acid Sites on CeO2-TiO2 Composite and 1-D TiO2 for Dye-Sensitized Solar Cells

“…Various aqueous solution-based methods for synthesizing crystallized CeO 2 nanoparticles (Masui et al, 2002a;Hirano et al, 2000;Li et al, 2001;Wu et al, 2002;Zhou et al, 2003;Bumajdad et al, 2004) and 1D, 2D and 3D CeO 2 nanostructures with different morphologies (Vantomme et al, 2005, Zhou et al, 2005, Kuiry et al, 2005, Ho et al, 2005Han et al, 2005;Sun et al, 2006;Zhong et al, 2007) have been investigated. Some of the properties of these materials, such as the dispersibility of the particles (Masui et al, 2002a) and their catalytic properties (Masui et al, 1997;Sun et al, 2006;Zhong et al, 2007) have also been studied.…”

Catalytic Hydrogen Production from Bioethanol

“…Also, since most of the active metal atoms are embedded in the matrix of support, resulting in less exposure of active metal on the sample surface, SG and CP prepared samples are more stable but less active than those prepared by impregnation. In addition, several novel preparation protocols such as hydrothermal [96], solvothermal [97], and microemulsion [98] have been developed to control the sample particle size and morphology which have been shown to be highly relevant to catalytic activity. On the other hand, most of the newly developed methods mentioned involve the employment of organic solvents, which could be harmful to the surroundings.…”