Preparation with a facile template-free method of uniform-sized mesoporous microspheres of rare earth (La, Ce, Pr, Nd) oxides

Autor: Mingyang Xing, Pengfei Ji, Feng Chen, Baozhu Tian, Jinlong Zhang, Segomotso Bagwasi
Rok vydání: 2011
Předmět:
Zdroj: Materials Research Bulletin. 46:1902-1907
ISSN: 0025-5408
DOI: 10.1016/j.materresbull.2011.07.027
Popis: Highlights: {yields} Mesoporous microspheres of light rare earth hydroxycarbonates and oxides were fabricated. {yields} The supersaturated urea has important effect on formation of mesoporous microspheres. {yields} The influences of [cation]/[urea] ratio and amount of water on the formation of spherical crystallites were discussed. -- Abstract: Mesoporous microspheres of light rare earth (La, Ce, Pr, Nd) hydroxycarbonates and oxides were successfully fabricated by a facile surfactant free hydrothermal method in supersaturated aqueous urea solution. The techniques of XRD, TEM, SEM, TG/DTA and N{sub 2} adsorption-desorption were employed to investigate the structure and formation process of mesoporous microspheres. It was revealed that supersaturated urea not only serve as a reactant and pH modifier in the reaction system but also guide the oriented assembly of hydroxycarbonate crystallites into microspheres by acting as a structure-directing agent. The microspheres of rare earth oxides could easily be obtained by simple calcination of corresponding hydroxycarbonates precursors without undergoing morphology changes. In addition, the influences of rare earth precursor and urea concentrations on the formation of microspheres were also investigated.
Databáze: OpenAIRE
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