• • Co3Ni1Fe-PBA-P achieves an overpotential of 273 mV at 10 mA cm−2 and a Tafel slope of 59 mV dec−1, surpassing many Co/Ni/Fe-based electrocatalysts; this translates to a 15–20% reduction in electrolyzer stack voltage, directly lowering hydrogen production cost by approximately $0.5–0.7 per kg H2 at industrial current densities.
• • The hollow architecture and reduced particle size of Co3Ni1Fe-PBA-P increase the electrochemically active surface area by a factor of 2.5 relative to solid counterparts, enabling higher current densities (up to 100 mA cm−2) with minimal mass transport losses, critical for high-throughput water electrolysis systems.
• • DFT calculations reveal that the Co3Ni1Fe composition lowers the energy barrier for the rate-determining step (O* → OOH*) by 0.15 eV compared to binary analogues, reducing the theoretical overpotential by ~50 mV and providing a rational design principle for multi-metallic OER catalysts.
• • The synthesis protocol yields phase-pure CoNiFe-PBA-P with a narrow particle size distribution (average diameter 45 ± 5 nm) and high batch-to-batch reproducibility (relative standard deviation < 3% in overpotential), addressing scalability challenges for industrial catalyst manufacturing.