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 IrO2 and RuO2 electrocatalysts. In this study, Fe-Ni coupled perovskite oxides, Pr0.5Ba0.5Fe1-xNixO3-delta, 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 Pr0.5Ba0.5Fe0.975Ni0.025O3-delta electrocatalyst demonstrates excellent activity for oxygen evolution reaction, favorably compared to other the state-of-the-art perovskite electrocatalysts. The encouraging results indicate that Pr0.5Ba0.5Fe1-xNixO3-delta series is a promising class of electrocatalysts for practical application of oxygen evolution reaction. (c) 2018 Elsevier Ltd. All rights reserved.