Engineering the oxygen-evolution activity by changing the A-site rare-earth elements in RSr₃Fe_1.5Co_1.5O_10−δ (R = La, Nd, Pr) Ruddlesden-Popper perovskites

The design of high-performance and low-cost catalysts for the oxygen evolution reaction (OER) is paramount for storing and converting clean and renewable energy. Ruddlesden-Popper (RP)-structured perovskite oxides show promising potential for efficiently catalyzing the OER. In this study, a series of RP-type perovskites RSr₃Fe_1.5Co_1.5O_10−δ (R = La, Nd, Pr) are synthesized and investigated to correlate their structure and physical structure properties with OER activities. Among the synthesized materials, PrSr₃Fe_1.5Co_1.5O_10−δ shows the best OER performance, evidenced by the smallest overpotential (294 mV) as well as the lowest Tafel slope (63 mV dec⁻¹). Such enhanced OER behavior is ascribed to larger electrochemically active areas, faster charge transfer rates, higher B-site valence state ions, more oxygen vacancies, and more favorable lattice oxygen oxidation (LOM) behavior. When applied in Zn-air batteries and water electrolyzers, PSFC also outperforms the benchmark catalyst RuO₂, suggesting that PSFC has the potential to be an outstanding OER electrocatalyst for practical applications. This study highlights the significance of adjusting A-site elements for improving OER activities.