Bifunctional Electrocatalysts for Green Hydrogen: A Brief Review of Design, Optimization, and Electrolyzer Applications

Abstract Bifunctional electrocatalyst systems offer a transformative pathway toward sustainable hydrogen generation. They uniquely simplify electrolyzer architectures, reduce precious metal dependencies, and enhance system performance for scalable green hydrogen production. This review examines recent advances in bifunctional oxygen evolution reaction/hydrogen evolution reaction (OER/HER) electrocatalyst systems for sustainable hydrogen synthesis. Water electrolysis governed by renewable electricity represents the cornerstone technology for green hydrogen generation, addressing global decarbonization challenges across multiple sectors. Recent breakthroughs in catalyst design have focused on developing high‐performance bifunctional materials capable of efficiently catalyzing both half‐reactions, thereby simplifying system architecture and reducing costs. Single‐atom catalysts (SACs), high‐entropy alloys (HEAs), and nanostructured composites have emerged as promising platforms, with several systems achieving remarkably low overpotentials for both reactions. Advanced characterization techniques, particularly operando methods, have provided unprecedented insights into reaction mechanisms and degradation pathways. The integration of artificial intelligence with high‐throughput experimental techniques presents promising pathways for accelerating catalyst discovery. This review critically analyzes material design strategies, engineering approaches, performance metrics, and durability considerations across alkaline water electrolyzer (AWE), anion exchange membrane (AEM), and proton exchange membrane (PEM) technologies, while examining sustainability implications through life cycle assessment and resource availability analysis for bifunctional electrocatalysts.