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Synthesis of Sr3Fe2O7and Investigation of the Effect of Pr in Sr Site and Co in Fe Site as a Dopant on the Microstructure and its Function as a Solid Oxide Fuel Cathode

Ghani Harzand, Ayda | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54769 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Nemati, Ali; Golmohammad, Mohammad
  7. Abstract:
  8. Nowday, one of the important goals of researchers is to develop and improve the properties of intermediate tempreture solid oxide fuel cells with range of 600-800˚C. Therefore, choosing the right material as a cathode with good performance in this temperature range is very important. For this purpose, various materials with ionic and electron conductivity mixtures (MIECs) are used, especially oxides with a Radelsden-Paper structure. These oxides are shown by the formula An+1BnC3n+1, which are actually composed of a combination of perovskite layers (ABO3) that are alternately superimposed between two layers of rock salt (AO). In the present study, Sr3Fe2O7 powder with different amounts (0.1, 0.2 and 0.3) of dopant Pr in Sr site and 0.2 Co in Fe site was synthesized by polymerization complex method. Also, the effect and amount of dopant on the electrical conductivity and electrochemical properties of the samples were investigated. XRD test was used to detect the phases formed after the calcination process. XRD results of all samples indicated the formation of Sr3Fe2O7 single phase powder. Also, to investigate the microstructure of the powder and the sintered sample, FESEM field emission scanning electron microscopy analysis, to check the electrical conductivity, four-point prob electrical conductivity test and to evaluate the electrochemical properties, the impedance test (EIS) were used. The results showed that with increasing the amount of Pr, the electrical conductivity increased and the polarization resistance decreased. Also, among all compounds, Sr2.7Pr0.3Fe1.8Co0.2O7-δ sample has the highest electrical conductivity of 95 S/cm at 400°C and the lowest polarization resistance of 0.68 Ω.Cm2 at 800°C
  9. Keywords:
  10. Solid Oxide Fuel Cell (SOFC) ; Electrochemical Properties ; Electrical Conductivity ; Ruddlesden-Popper Cathodes ; Perovskite Catalyst ; Sr3Fe2O7 Catalyst

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