Abstract
<jats:p>Perovskite oxides have emerged as promising electrocatalysts for the oxygen evolution reaction (OER) in alkaline media due to their flexible electronic structures, rich redox chemistry, and excellent stability under oxidative conditions, yet their performance remains constrained by sluggish charge transfer and limited active site utilization. In this work, a double A-site substituted layered perovskite, Pr0.5Nd0.5Ba0.5Sr0.5Fe2O5+δ (PNBSF), was successfully spray-coated onto nickel foam (NF) to fabricate a self-supported PNBSF@NF electrode with enhanced OER performance. Density functional theory (DFT) calculations reveal that oxygen vacancies located at different lattice positions effectively modulate the electronic structure of PNBSF, optimize the Fe–O bonding environment, and significantly reduce the oxygen adsorption energy, thereby facilitating OER kinetics. Electrochemical measurements demonstrate that PNBSF@NF requires a low overpotential of 297 mV to reach 100 mA cm-2, along with a favorable Tafel slope of 97.68 mV dec-1. Moreover, the electrode exhibits excellent long-term durability, maintaining stable performance for over 100 h in both 1 M and 6 M KOH electrolytes. When integrated into a membrane electrode assembly, the Pt/C/PPS/PNBSF@NF electrolyzer delivers a high current density of 1.587 A cm-2 at 2 V and 80 °C, outperforming the Pt/C–NF counterpart. Post-reaction characterizations confirm the structural stability of PNBSF with only slight surface reconstruction, underscoring its potential as a cost-effective and efficient OER catalyst for practical alkaline water electrolysis.</jats:p>