Novel LaFe₂O₄ spinel structure with a large oxygen reduction response towards protonic ceramic fuel cell cathode

Highly active and stable electrocatalysts are mandatory for developing high-performance and long-lasting fuel cells. The current study demonstrates a high oxygen reduction reaction (ORR) electrocatalytic activity of a novel spinel-structured LaFe ₂O ₄ via a self-doping strategy. The LaFe ₂O ₄ demonstrates excellent ORR activity in a protonic ceramic fuel cell (PCFC) at temperature range of 350–500 °C. The high ORR activity of LaFe ₂O ₄ is mainly attributed to the facile release of oxide and proton ions, and improved synergistic incorporation abilities associated with interplay of multivalent Fe ³⁺/Fe ²⁺ and La ³⁺ ions. Using LaFe ₂O ₄ as cathode over proton conducting BaZr _0.4Ce _0.4Y _0.2O ₃ (BZCY) electrolyte, the fuel cell has delivered a high-power density of 806 mW/cm ² operating at 500 °C. Different spectroscopic and calculations methods such as UV–visible, Raman, X-ray photoelectron spectroscopy and density functional theory (DFT) calculations were performed to screen the potential application of LaFe ₂O ₄ as cathode. This study would help in developing functional cobalt-free ORR electrocatalysts for low temperature-PCFCs (LT-PCFCs) and SOFCs applications.