Combustion synthesis, structural and magnetic characterization of Ce1−xPrxO2 system

• Published in: Journal of materials science. Materials in electronics 2017-11, Vol.28 (21), p.16358-16365
• Main Authors: Cruz Pacheco, A. F., Gómez Cuaspud, J. A., Parra Vargas, C. A., Carda Castello, J. B.
• Format: Article
• Language: English
• Subjects: Cerium oxides; Characterization and Evaluation of Materials; Chelation; Chemistry and Materials Science; Citric acid; Combustion synthesis; Crystal structure; Diamagnetism; Electron microscopy; Heat; Infrared analysis; Infrared spectroscopy; Magnetic properties; Materials Science; Nitrogen; Optical and Electronic Materials; Point defects; Praseodymium; Praseodymium oxide; Spectrum analysis; Storage capacity; Structural analysis; Thermal analysis; X-ray diffraction
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-017-7546-6

The current work describes the synthesis of Ce 1−x Pr x O 2 (x = 0.0, 0.2, 0.4, 0.6, 0.8) and Pr 6 O 11 systems by the combustion method, using citric acid as chelating agent. The obtained solids after combustion and calcination processes were characterized by thermal analysis (TGA-DTA) and infrared spectroscopy (FT-IR) to evaluate the chemical process during the combustion reaction. The surface area analysis using isotherms of nitrogen adsorption, reveal that all samples exhibit values between 70 and 135 m 2  g −1 , with a pore volume that allows its classification as mesoporous materials. The structural analysis by X-ray diffraction (XRD) and Rietveld refinement, revealed the obtention of a pure cubic structure Fm3m (225) along all cerium oxide modifications with nanocrystalline domain sizes, except for the praseodymium oxide that shows two crystalline phases in a monoclinic crystalline phase P12 1 / c 1 (14) in the case of Pr 6 O 11 and a cubic phase Fm3m (225) for PrO 2 oxide. The oxygen storage capacity measurements performed in all samples, demonstrate that exchange of Ce ions by Pr increases the storage capacity of samples over the reference values in accordance with the synthesis method. The characterization by high-resolution transmission electron microscopy, confirmed that the solids are composed by nanometric aggregates with d spacing between 0.29 and 0.31 nm along main diffraction signals, in accordance with the experimental XRD results. Finally, the magnetic characterization in a ZFC configuration and a M-H mode, shows a strong paramagnetic behavior in all systems except in CeO 2 oxide, which exhibited a prevalent diamagnetic behavior.