Redox properties of nanostructured lanthanide-doped ceria spheres prepared by microwave assisted hydrothermal homogeneous co-precipitationElectronic supplementary information (ESI) available: Structural parameters and standard Rietveld agreement factors for nanostructured LnDC spheres are presented in Tables S1-S4, SR-XRD patterns in the vicinity of the 111 reflection for nanostructured LnDC spheres are exhibited in Fig. S1-S4 and the Ce L3-edge XANES spectra of the nanostructured GDC10, GDC20,

• Main Authors: Muñoz, F. F, Acuña, L. M, Albornoz, C. A, Leyva, A. G, Baker, R. T, Fuentes, R. O
• Format: Journal Article
• Language: English
• Published: 27.11.2014
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c4nr05630b

In this work, nanostructured Ln x Ce 1− x O 2− δ (Ln: Gd and Pr; x = 0.1 and 0.2) spheres were synthesized by microwave assisted hydrothermal homogeneous co-precipitation and their properties were characterized by synchrotron radiation XRD, X-ray absorption near-edge spectroscopy (XANES) and scanning and high-resolution electron microscopy (SEM and HRTEM). In situ XRD and XANES experiments were carried out under reducing and oxidizing conditions in order to investigate the redox behaviour of these materials. The nanostructured mixed oxide spheres were found to have a cubic crystal structure ( Fm 3 m space group). The spheres were composed of nanoparticles with an average crystallite size of about 10 nm. The Ln 0.1 Ce 0.9 O 2− δ compositions exhibited the highest specific surface area (∼60 m 2 g −1 ). In situ XRD experiments showed an increase in lattice parameters upon reduction, which was attributed to the reduction of Ce 4+ and Pr 4+ cations to Ce 3+ and Pr 3+ , which have larger radii, and to the associated increase in V O concentration. This increase in lattice parameters was considerably more pronounced for PrDC than GDC, and was explained by the considerably larger change in ionic radius for Pr upon reduction. XANES absorption experiments at the Ce and Pr L 3 -edge showed that the changes observed upon reduction of the Pr-containing samples resulted mostly from the formation of Pr 3+ rather than Ce 3+ , and supported the previously reported proposal that Pr 3+ has a stabilizing effect on Ce 4+ . The effect of doping with univalent (Gd 3+ ) and multivalent (Pr 3+,4+ ) cations on redox properties of novel nanostructured lanthanide-doped ceria spheres obtained by microwave assisted hydrothermal method was studied.