Insights into Ni-Fe couple in perovskite electrocatalysts for highly efficient electrochemical oxygen evolution.

Abstract Electrochemical oxygen evolution reaction is an appealing way to alleviate energy and environmental crisis. Perovskite oxides are supposed as attractive low-cost alternative electrocatalysts for oxygen evolution reaction relative to the IrO 2 and RuO 2 electrocatalysts. In this study, Fe-Ni coupled perovskite oxides, Pr 0.5 Ba 0.5 Fe 1-x Ni x O 3-δ , are proposed as novel electrocatalysts for oxygen evolution reaction in alkaline solution. The electrocatalytic activity of perovskites are optimized by engineering the couple of Fe-Ni cations. We identify a possible correlation between the enhancement in the activity and the amount of surface oxygen vacancies, OH− adsorption, charge transfer kinetics as well as e g -filling. The Pr 0.5 Ba 0.5 Fe 0.975 Ni 0.025 O 3-δ electrocatalyst demonstrates excellent activity for oxygen evolution reaction, favorably compared to other the state-of-the-art perovskite electrocatalysts. The encouraging results indicate that Pr 0.5 Ba 0.5 Fe 1-x Ni x O 3-δ series is a promising class of electrocatalysts for practical application of oxygen evolution reaction. Graphical abstract Image 1 Highlights • A novel family of perovskite electrocatalysts is proposed for OER. • The activity and stability for OER is enhanced by engineering Fe-Ni couple. • The performance of PBFN2.5 rivals other perovskite electrocatalysts. [ABSTRACT FROM AUTHOR]