Rongshuo Liang, Linsen Li, Shan Huang, Zhao Jiang, Jiayuan Li
We report an ordered L11-PtCu3@C intermetallic catalyst that achieves exceptional Pt mass activity of 15 A mgPt-1 for the hydrogen evolution reaction (HER), outperforming most state-of-the-art Pt-based intermetallics. When integrated into a proton exchange membrane (PEM) electrolyzer, this catalyst enables highly efficient and durable hydrogen production with favorable economic viability, demonstrating its potential as a cost-effective and high-performance electrocatalyst for practical green hydrogen generation.