Study the Properties of Gadolinium-Doped Ceria Nano-Powders Synthesized Via Sol–Gel Method with New Precursors (original) (raw)
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Microwave-assisted synthesis of gadolinia-doped ceria powders for solid oxide fuel cells
Ceramics International, 2011
Gadolinia doped ceria (GDC) is an attractive electrolyte material for intermediate temperature solid oxide fuel cells (IT-SOFCs) for its high ionic conductivity at low temperature (500-700 8C). A number of different methods are currently used to prepare nano-sized doped-ceria powder. Among the others, precipitation in solution remains the best method to obtain well-dispersed particles of controlled properties. In this work, nanocrystalline Ce 1Àx Gd x O 2Àd (GDC) particles were produced by polyol microwave assisted method in very mild conditions (170 8C, 2 h, 1 atm). The as-synthesized powder showed good sinterability and ionic conductivity comparable to the ones of the corresponding nanometric commercial GDC. #
Preparation by different methods and analytical characterization of gadolinium-doped ceria
Chemical Papers, 2017
The present work reports the influence of chemical synthesis on structural, morphological and optical properties of gadolinium-doped ceria (GDC) with analytical characterization of synthesized specimens. GDC powders with Gd content of 10, 15 and 20 mol% were synthesized by aqueous sol-gel and sol-gel combustion methods using glycerol as complexing agent and fuel. The phase purity and structural features of obtained powders were evaluated using X-ray diffraction analysis and Raman spectroscopy. These studies confirmed that crystallization of GDC occurs into cubic fluorite-type crystal structure. Morphological features as well as optical properties of GDC powders were determined to be strongly dependent on the synthesis method. To confirm chemical composition of prepared samples, spectrophotometric approach for the determination of Ce and Gd in GDC samples was suggested. Relative standard deviation values for Ce and Gd were in the range of 1.5-4.1 and 2.0-5.6%, respectively. The obtained results demonstrated that the suggested analytical procedure can be successfully used for the analysis of GDC specimens with high accuracy.
Gadolinium-doped ceria nanopowders synthesized by urea-based homogeneous co-precipitation (UBHP)
Gadolinium (10%)-doped ceria was successfully synthesized by using an urea-based co-precipitation method (UBHP). A single fluorite phase was obtained after a low temperature (400 ͦC) calcination treatment. The resulting powders showed grains of nanometric size with some agglomerations and an overall good sinterability. Pellets were sintered at 1300 and 1500 ͦC for 3 h. The ionic conductivity was measured by electrochemical impedance spectroscopy measurements and a correlation between electrical properties and microstructure was revealed. The promising conductivity values showed that the synthesized powders are suitable for intermediate temperature solid oxide fuel cells (IT-SOFCs) applications.
Gadolinium Doped Ceria Nanocrystals Synthesized From Mesoporous Silica
Journal of Nanoparticle …, 2008
Highly crystalline and thermally stable gadolinium doped ceria (GDC) particles have been synthesized by hard template route for the first time. This oxide is being recognized as an intermediate temperature (500-700°C) electrolyte material for applications in solid-oxide fuel cells. The GDC particles show high crystallinity and nanometric size (2.83 ± 0.05 nm in diameter) and Raman analyses confirm the formation of the solid solution instead of a CeO 2 and Gd 2 O 3 mixture. EDX and EELS studies indicate a stoichiometry coherent with the Gd 0.2 Ce 0.8 O 1.9 phase. The synthesized nanometric powder is expected to be used in solid oxide fuel cells as well as in the catalytic treatment of automobile exhaust fumes.
Synthesis and Characterization of Nanosize Ceria-Gadolinia Powders
Journal of the Ceramic Society of Japan, 2005
Three dierent methods of synthesis of ceriagadolinia (CGO) nanopowders are presented. We established a technique of the synthesis of uniformly aggregated, agglomeratefree CGO in which ceriagadolinia composite nanoaggregates (1540 nm) are prepared by nucleation and crystallization of ceria on the surface of preliminary synthesized, hydrolyzed and ultrasonically deagglomerated gadolinia (317 nm). Nanosize aggregates (1265 nm) of CGO were produced during subsequent nonisothermal calcination. The incorporation of the small con centrations of gadolinia in the ceria lattice was studied using the electron spin resonance technique. It was con rmed that Gd 3{ occupies the sites of both cubic and axial symmetry. With increasing concentration, Gd 3{ forms a defect complex with the oxygen vacancy.
Electrolyte materials for solid oxide fuel cells derived from metal complexes: Gadolinia-doped ceria
Ceramics International, 2012
Gadolinia doped ceria (GDC) powders with different gadolinium contents were successfully prepared by the thermal decomposition of ceria complexes. All the calcined powder samples were found to be ceria-based solid-solutions having a fluorite-type structure. The powders were coldisostatically pressed and sintered in air at 1500 8C for 5 h to attain a sintered density of about 90% of its theoretical value. The electrical conductivity of the GDC pellets in air was studied as a function of temperature in the 225-700 8C range, by using two-probe electrochemical impedance spectroscopy measurements. The highest total conductivity (s 600 8C = 0.025 S/cm) was found for the Ce 0.85 Gd 0.15 O 1.925 composition.
IOP Conference Series: Materials Science and Engineering, 2019
Cerium oxide base materials have been attracting great attention as a promising electrolyte for intermediate temperature of solid oxide fuel cell (IT-SOFC) due to its excellent conductivity at a lower temperature. In this works, cerium from Indonesia local raw material was developed as a cheaper alternative precursor for preparing gadolinium doped cerium (Ce0.9Gd0.1O1.95 or GDC10) electrolyte. The effects of polyethylene glycol 400 (PEG 400) as a surfactant on to physical properties of GDC10 electrolyte were studied. GDC10 powders were synthesized using co-precipitation method with the addition of various PEG 400 concentration i.e 0,1,2 and 3v/v%. Synthesized powders were characterized by using X-Ray Diffraction (XRD), Particle Size Analyzer (PSA), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and Fourier Transform Infrared (FTIR) Spectroscopy. The XRD analysis indicates that crystallinity was enhanced and all of the peaks on samples correspond to the fluo...
Journal of Spectroscopy, 2016
The nanopowdery solid solutions of multidoped ceria Ce0.8Nd0.0025Sm0.0025Gd0.005Dy0.095Y0.095O2-δ(x=0.2) with the fluorite type crystal structure of CeO2were synthesized for the first time. Two synthesis procedures were applied: the modified glycine-nitrate procedure (MGNP method) and room temperature self-propagating reaction (SPRT method). All nanopowders were characterized by XRPD analysis, Raman spectroscopy, low temperature nitrogen physisorption, TEM, and SEM methods. According to the XRPD and Raman spectroscopy results, single phase solid solutions of fluorite structure were evidenced regardless of the number of dopants and synthesis procedure. Both XRPD and TEM were analyses evidenced nanometer particle dimensions. The SPRT method results in obtaining sample with higher specific surface area, smaller crystallite and particles sizes, and the same values of the lattice parameter in comparison to pure CeO2. Raman spectroscopy was confirmed to the oxygen vacancies introduced int...
Synthesis and Characterization of Co-Doped Ceria Ceramics by Sol-Gel Method
Transactions of the Indian Ceramic Society, 2011
Doped and co-doped ceria electrolyte materials are very useful in solid oxide fuel cells. The Ce 0.9 Sm 1-x Sr x O 2 (x = 0-0.09) compositions were synthesized through the sol-gel method. Dense Ce 0.9 Sm 1-x Sr x O 2 ceramics were obtained through sintering the pellets at 1300 o C for 8 h. XRD measurements indicate that all synthesized materials crystallized in cubic fluorite-type structure. Average crystallite size of the samples was in the range 21-27 nm. The relative density of Ce 0.9 Sm 1-x Sr x O 2 samples was over 94% of the theoretical density. The lattice parameter increased linearly with increasing Sr concentration in Ce 0.9 Sm 1-x Sr x O 2 following Vegard's rule. Surface morphology was analyzed using SEM. It was observed that the thermal expansion increased linearly with increasing temperature. The two-probe a.c. impedance spectroscopy was used to study the grain, grain boundary and total ionic conductivity of doped and co-doped ceria in the temperature range 250 o-500 o C. The Ce 0.9 Sm 0.07 Sr 0.03 O 2 composition showed higher grain ionic conductivity and minimum activation energy at 500 o C.