Morphology control and characterization of broom-like porous CeO2

Abstract

In this study, CeO 2 with a broom-like porous hierarchical structure was successfully prepared by a simple template-free hydrothermal method. In the whole hydrothermal process, reaction time and temperature play important roles in morphology control. The morphology of the as-prepared samples was characterized by field emission scanning electron microscopy, transmission electron microscopy and high-resolution transmission electron microscopy. Structure information was obtained by using an X-ray diffractometer and Raman analysis. Analyses of elements and chemical valence analysis were carried on X-ray photoelectron spectroscopy. Absorption edge and band gap energy were investigated by UV-vis diffuse reflectance. In addition, the optimum experimental conditions for target products were determined. Compared with various morphology samples' BET data, relative intensity of Raman peaks, catalytic evaluation, we can draw a conclusion that CeO 2 with a broom-like porous hierarchical structure has a higher concentration of oxygen vacancies that results in enhancement of catalytic activity. An Ostwald ripening process with orientative self-assembly was proposed for formation of the broom-like porous hierarchical structure.

Synthesis and photocatalytic performance of yttrium-doped CeO2 with a hollow sphere structure

“…The shift at ~460 cm -1 can be assigned to F2g vibration of the fluorite-type structure and it can be considered as the symmetric stretching mode of oxygen atoms around cerium ions, and the molecule retains its tetrahedral symmetry throughout. Based on the results of previous studies and our own studies [43][44][45], a weak and less prominent band near ~600…”

“…First, 0.87 g cerium nitrate (Ce(NO 3 ) 3 •6H 2 O) and 0.07 g yttrium nitrate (Y(NO 3 ) 3 •6H 2 O) were dissolved in 100 ml of deionized water with vigorous magnetic stirring for 30 minutes at room temperature. Based on the optimum dopant concentration determined in previous studies [45], we used the optimal mole ratio of 1:0.1 for cerium nitrate and yttrium nitrate.…”

“…When the number of oxygen vacancies is larger, the oxygen ion mobility becomes higher. Transportation mobility of lattice oxygen ions is beneficial for the separation of photogenerated electrons and holes [43][44][45]. In another word, the recombination of photogenerated electrons and holes is restricted at a higher oxygen vacancy.…”

“…The main fabrication methods are hydrothermal methods with surfactants and modifying agents. Our group has fabricated yttrium-doped ceria with hedgehog-like [43] and porous broom-like [44][45] hierarchical structures by using a template-free hydrothermal process.…”

Controlled synthesis and magnetic properties of thin CeO2 nanotubes by a facile template-free hydrothermal method

“…In recent years, there has been growing interest in the controlled synthesis of higher ordered inorganic crystals with specific dimensions and well-defined shapes because of the unique shape-dependent materials properties, which would result in a wide range of electrical, optical, or magnetic properties and open a new domain of theoretical and technological interest [1][2][3][4]. Therefore, considerable efforts have been focused on the fabrication of nanomaterials with various morphology structures owning to stimulated by the fantastic and remarkable properties.…”