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A Highly Efficient Bifunctional Electrode Fashioned with in situ Exsolved NiFe Alloy over Ruddlesden-Popper Oxide for Reversible Solid Oxide Cells

Title of paper
A Highly Efficient Bifunctional Electrode Fashioned with in situ Exsolved NiFe Alloy over Ruddlesden-Popper Oxide for Reversible Solid Oxide Cells
Author
[김원배 교수 연구실] 나노입자 활용 고체산화물 연료전지 전극개발
Publication in journal
ACS Sustainable Chem. Eng. 10 (2022) 7595-7602.
Publication date
20220613

 

[Abstract]


We developed a bifunctional electrode of Pr0.8Sr1.2(Fe,Ni)0.8Nb0.2O4−δ (R.P.PSFNNb) fashioned with in situ exsolved Ni-Fe alloy nanoparticles (NPs) for electrochemical oxidations of H2, CO, and syngas as well as CO2 electrolysis. The NiFe-R.P.PSFNNb was prepared by in situ phase transition of Pr0.4Sr0.6Fe0.8Ni0.1Nb0.1O3−δ (PSFNNb) along with exsolution of Ni-Fe alloys in a reducing atmosphere, as confirmed by X-ray diffraction and X-ray photoelectron spectroscopy (XPS) characterization. XPS and H2-temperature-programmed reduction analyses were also conducted to examine the behavior of the exsolution process. Transmission electron microscopy and electron energy loss spectroscopy element mapping concluded that the Ni-Fe alloy NPs were successfully exsolved and anchored on the parent oxide material. The NiFe-R.P.PSFNNb exhibited superior electrochemical performance for fuel electrode reactions of reversible solid oxide cells (RSOCs). A maximum peak power density of 829, 522, and 749 mW·cm–2 was obtained for the electrochemical oxidations of H2, CO, and syngas, respectively, and a high current density of −1.89 A·cm–2 was produced in the electrochemical reduction of CO2 to CO at a temperature of 850 °C. More interestingly, no significant degradation of the electrochemical performance was observed in both operating modes, indicating that the NiFe-R.P.PSFNNb proposed in this work could be a promising candidate as a bifunctional electrode for the practical implementation of RSOCs.

 

DOI: 10.1021/acssuschemeng.2c01360
Link: https://pubs.acs.org/doi/10.1021/acssuschemeng.2c01360