(701f) Design of Non-Stoichiometric Mixed Metal Oxides Toward the Advancement of Intermediate Temperature Solid Oxide Fuel Cells
In this work, we will discuss our efforts toward obtaining structure-performance relations that can guide the development of optimal R-P oxides for oxygen reduction at intermediate temperature SOFCs. The activity of nanostructured mixed metal oxides with varying surface morphology and composition (i.e. La2Ni1-xMxO4+Î´, with M= Fe, Co and Cu and 0 â¤ xâ¤ 0.25) is systematically evaluated using a combined theoretical and experimental approach.1-2-3 The kinetics of the electrochemical oxygen reduction reaction (ORR) on nanostructured R-P oxides are investigated by means of electrochemical impedance spectroscopy. Two main electrochemical processes governing the polarization resistances during ORR have been identified: the electron transfer/oxygen vacancy healing, and the oxygen ion transfer through the electrocatalyst/electrolyte interface. We find that the nanostructure and composition of R-P oxides significantly effects these processes. Furthermore, we show that the incorporation of optimized nanostructured R-P oxides as SOFC cathode electrocatalysts leads to significant improvement in the cell performance. These findings provide important insights into tuning complex mixed ionic-electronic oxides for enhancing oxygen reduction kinetics in intermediate temperature ceramicâbased fuel cells.
- Ma, X. F.; Carneiro, J. S. A.; Gu, X. K.; Qin, H.; Xin, H. L.; Sun, K.; Nikolla, E., Engineering Complex, Layered Metal Oxides: High-Performance Nickelate Oxide Nanostructures for Oxygen Exchange and Reduction. Acs Catal 2015, 5 (7), 4013-4019.
- Carneiro, J. S. A.; Brocca, R. A.; Lucena, M. L. R. S.; Nikolla, E., Optimizing cathode materials for intermediate-temperature solid oxide fuel cells (SOFCs): Oxygen reduction on nanostructured lanthanum nickelate oxides. Appl Catal B-Environ 2017, 200, 106-113.
- Gu, X. K.; Nikolla, E., Design of Ruddlesden-Popper Oxides with Optimal Surface Oxygen Exchange Properties for Oxygen Reduction and Evolution. Acs Catal 2017, 7 (9), 5912-5920.