Abstract
The perovskite Lanthanum Strontium Cobalt Ferrite (LSCF) is investigated as the cathode material used in intermediate-temperature solid oxide fuel cells (IT-SOFCs). In the present study, La0.6−xDyxSr0.4Co0.2Fe0.8O3−δ (x = 0, 0.3, 0.6) was synthesized through the coprecipitation method. The obtained precipitate was calcined at 500, 700, 900, and 1000°С. Phase characterization of the synthesized LSCF and LDySCF powder before and after heat treatment at 700°С was carried out by X-ray diffraction (XRD) analysis. XRD patterns revealed that the perovskite phase was obtained at 700°С in all calcined samples. Chemical bond study to investigate the synthesis process was conducted using the Fourier transform infrared spectroscopy technique. Thermal analysis of DTA and TG has been utilized to investigate how the calcination temperature affects the perovskite phase formation. According to the STA results, the perovskite phase formation started at 551°С and completed at 700°С. The density values of synthesized powders were 6.10, 6.11, and 6.37 g·cm−3for the undoped and doped samples calcined at 700°С. Powder morphology was studied by field emission scanning electron microscopy (FE-SEM). The micrographs showed the spherical-shaped particles with the average particle size of 24–131 nm.
Highlights
IntroductionThe lower calcination temperature for the obtained sol-gel powder can be attributed to the polymerization process that occurs during the sol-gel method
One important reaction in a solid oxide full cell is the oxygen reduction reaction (ORR); Lu Zhang et al investigated the effect of CaO additive on ORR reaction kinetics. ey added CaO nanoparticles to the porous LSCF structure via the infiltration method. ey observed that there was no reaction between CaO and LSCF indicating compatibility of LSCF and CaO within the moderate operating temperature range. eir impedance spectrum observations indicate that CaO nanoparticles can effectively reduce the polarization resistance of the LSCF cathode and LSCFSDC composite cathode as well [6]
After heat treatment of the dried coprecipitation-yielded powder at 500°S, the LaFeO3perovskite phase (JCPDS card No 82–1958) was emerged besides of La2O3, SrCO3, Fe3O4, and Co3O4. e X-ray diffraction (XRD) pattern of the sample calcined at 700°S reveals that the perovskite LSCF (JCPDS card 82–1961) [13] was formed simultaneous with La2O3 and a little amount of SrCO3 as secondary phases
Summary
The lower calcination temperature for the obtained sol-gel powder can be attributed to the polymerization process that occurs during the sol-gel method They have deduced that the CuO nanoparticles acted as catalysts reduced the activation energy needed for perovskite phase formation in both synthesis methods. It is worth mentioning that the low coverage of CuO particles on LSCF enhanced the oxygen reduction reaction kinetics [10] Another proposed idea is to combine different methods in purpose of acquiring proper quality achievement such as the study has conducted by Fansuri et al ey have mixed solid state and mechanochemical routes to attain powder with fine particle size after optimum time of milling [11].
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