Studies of sintering effects in electrical and electrocatalytic properties of LaNi1-xFexO3 (x = 0; 0.3; 0.6; 0.9) series
| Reference | Presenter | Authors (Institution) | Abstract |
|---|---|---|---|
| 06-203 | Mario Rodrigo dos Santos Soares | Gozzo, C.B.(Federal University of Sao Carlos); Soares, M.R.(Federal University of Sao Carlos); Leite, E.R.(Centro Nacional de Pesquisa em Energia e Materiais); | The perovskite LaNiO3 is a widely studied material, for example, as cathode in solid oxide fuel cells, in hydrogen production from reforming of ethanol and as bifunctional catalyst in oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). We will show the effect of the sintering in electrical and electrocatalytic properties of the LaNi1-xFexO3 (x = 0; 0.3; 0.6; 0.9) series. For this, samples were synthesized by the co-precipitation method and sintered in temperatures from 950 oC to 1300 oC. We performed a systematic characterization by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, as well as, electrical and electrochemical measurements. LaNiO3 and LaNi0.7Fe0.3O3 showed a single phase indexed with the rhombohedral phase (ICSD – 84933) and the others samples were indexed with the orthorhombic structure of the LaFeO3 (ICSD – 029234). It was observed that the relative density increased with the increasing of temperature, but LaNiO3 was decomposed in La2NiO4. The addition of Fe3+ ions stabilized the structure of the perovskite in high temperature, but the conductivity decreased with this. The sample LaNi0.7Fe0.3O3 sintered at 950 °C showed the higher conductivity (2.07x10-2 S.cm-1) than the LaNiO3 pure (5.95x10-3 S.cm-1) and the others sintered pellets. Considering the OER, LaNiO3 showed low overpotential (420 mV) at 10 mA/cm2, however the ceramic electrode with 0.3 Fe3+ presented lower overpotential (340 mV). These results show to us the improvement of properties of lanthanum nickelate when doped with Fe3+, therefore bringing the possibility of application of this materials on renewable energy devices. Acknowledgements: FAPESP (CEPID - 2013/07296-2 and 2017/03135-5), FINEP, CAPES, CNPq |
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