Structural and electrical properties of Sm and Er co-doped ceria electrolytes

The aim of this study is to prepare Er and Sm co-doped CeO(2)electrolytes via the Pechini method and investigate the effects of simultaneous addition of Sm and Er on the structural and electrical features of CeO2. The structural, functional group analysis, microstructures, and electrical properties of the electrolyte samples are conducted by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and impedance spectroscopy (IS). All the calcined and sintered electrolytes were obtained with cubic fluorite crystal structure without secondary oxide phases. After sintering at 1400 degrees C, highly dense electrolytes were achieved (> 90%). The IS measurements indicated that the highest ionic conductivity was observed for the singly doped Ce0.80Sm0.20O1.90(sigma(750 degrees C)= 3.86 x 10(-2)S/cm) electrolyte. sigma(750 degrees C)was found to be 3.82 x 10(-2), 1.73 x 10(-2), 0.61 x 10(-2)S/cm for Ce0.80Er0.05Sm0.15O1.90, Ce(0.80)Er(0.10)Sm(0.10)O(1.90)and Ce0.90Er0.10O1.95, respectively

Preparation of Sm0.2Ce0.8O1.9 electrolytes via the chitosan templating method and investigation of the sintering behavior

Sm0.2Ce0.8O1.9 electrolytes were prepared using a novel chitosan templating method. To examine the sintering kinetics of the materials, 5 minutes, 1 hour, and 6 hours of sintering processes were carried out at 1200, 1300, and 1400 degrees C. The phase structure of the sintered samples was clarified by XRD analysis. The morphological structure was examined by SEM and the average grain sizes were calculated with the Linear Intercept Method. The dominant diffusion mechanism and grain growth activation energies during sintering were calculated for the SDC20 electrolytes synthesized by the chitosan templating method for the first time. In addition to the sintering study, the ionic conductivities of the samples were determined by electrochemical impedance spectroscopy. The maximum O2- conductivity value for the 1300-6 sample was found to be 0.052 S.cm(-1). The study showed that the chitosan templating method is an effective way of synthesizing SDC20 materials

Synthesis of Al2O3, MgO and MgAl2O4 by solution combustion method and investigation of performances in partial oxidation of methane

Al2O3, MgO and MgAl2O4 nanocrystalline and mesoporous materials were prepared by simple solution combustion synthesis using urea and metal nitrates and the effect of metal nitrate/urea ratio was investigated. The metal oxides that were found suitable for catalytic purposes were tested in catalytic partial oxidation of methane (CPOM). It was observed that the oxidizer/fuel ratio could affect the structure phase, crystallinity and morphology of the synthesized materials. gamma-Al2O3 was obtained when the equivalence ratio was 2, and at lower ratios, the obtained phase was alpha-Al2O3. The cubic MgO phase was obtained at each ratio but the material yield was low below the equivalence ratio of 4. Highly crystalline MgAl2O4 was obtained at fuel-rich conditions only. 10% (wt.) Ni loaded MgAl2O4-2 and MgO-4 showed high activity (>90% CH4 conversion) and product selectivity (>98% H-2 and CO selectivity) at 800 degrees C under 157,5001 kg(-1) h(-1). (C) 2019 Elsevier B.V. All rights reserved