Theoretical Investigation of the Oxygen Interaction on Co-doped YFeO_3-δ as a Novel Cathode for Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are ideal devices for converting energy since they combine fuel flexibility with high efficiency. Understanding oxygen reduction reaction (ORR) is vital to developing and designing novel cathode materials for low-temperature operation in SOFCs. In this work, the first-principle theory has been applied to explore the interaction of oxygen molecules on YFe_0.5Co_0.5O₃ (YFC) which could be used as a novel perovskite cathode. The oxygen species are investigated by the analyses of electronic structure and differential charge density. It is found that a strong hybridization between transition metals (Co/Fe) and O when oxygen molecular adsorbed on YFC surface. Cobalt dopant is demonstrated to play a critical role in decreasing the reaction barrier by comparing the minimum energy paths (MEPs) of ORR. Furthermore, the increase in the O 2p band center also proves that YFC with the partial substitution of Fe by Co could improve the catalytic activity of ORR. Graphical Abstract: The minimum energy paths (MEPs) of the ORR on the surfaces of YFC (1 1 0). [Figure not available: see fulltext.]