Femtosecond‐Laser Synthesized PtBi Nanoalloys for Efficient Methanol Oxidation in Hybrid Electrolysis

Hydrogen production through electrochemical seawater splitting is challenged by the energy‐intensive oxygen evolution reaction and the competing chlorine evolution reaction. To overcome these obstacles, ligand‐free platinum bismuth (PtBi) alloy nanoparticles (≈2 nm) are synthesized via femtosecond laser liquid ablation under nonequilibrium conditions, yielding metastable structures with tunable elemental compositions populated with defects. The Pt 4 Bi/C catalyst excels in alkaline methanol oxidation reaction (MOR), delivering a mass activity of 17.7 A mg −1 pt (11.5 times higher than 20% Pt/C) and a specific activity of 54.9 mA cm −2 . In‐situ Fourier transform infrared spectroscopy and ambient pressure X‐ray photoelectron spectroscopy reveal a CO‐free pathway enabled by Bi, reducing catalyst poisoning. Density functional theory calculations show that PtBi─O lowers d‐band center of Pt, weakening the adsorption of *CO, promoting the adsorption of *OH, and lowering the energy barrier from *CHO to *HCOOH. As an example, a hybrid MOR–hydrogen evolution reaction (HER) electrolyzer demonstrates reduced voltage, suppresses side reactions, improves catalyst durability, achieves 545 mV at 10 mA cm −2 , and maintains stability for 54 h below 1.1 V in natural seawater. This study demonstrates the efficacy of PtBi nanoalloys in efficient MOR catalysis for hybrid electrolysis systems toward sustainable hydrogen production.