Femtosecond laser-fabricated defect-rich PtRe alloy clusters for enhanced alkaline hydrogen evolution

The sluggish kinetics of the alkaline hydrogen evolution reaction (HER) stemming from *OH poisoning on Pt-based catalysts pose a barrier to efficient anion exchange membrane water electrolyzers (AEMWEs). To address this, we developed a non-equilibrium femtosecond laser ablation in liquid (fs-LAL) method to synthesize defect-rich PtRe alloy clusters (∼1.88 nm). This method overcomes thermodynamic immiscibility between Pt and Re, enabling metastable alloys with rich structural defects and lattice distortions, unattainable by conventional methods. The optimized Pt₁₅Re/C catalyst delivers superior alkaline HER performance in 1 M KOH, with an overpotential of 12.6 mV at 10 mA cm⁻², surpassing commercial Pt/C (23.9 mV). In an AEMWE, the catalyst achieves an industrial current density of 1.0 A cm⁻² at 1.68 V (60 °C) with stability over 350 h, surpassing most reported counterparts. Density functional theory (DFT) calculations, using a PtRe cluster, reveal a synergistic dual-site mechanism: oxophilic Re atoms facilitate H₂O activation and *OH adsorption, alleviating poisoning on adjacent Pt sites, which maintain near-optimal hydrogen adsorption free energy (ΔG_H⁎) for efficient H* desorption. This work demonstrates the efficacy of non-equilibrium synthesis for creating metastable bimetallic clusters, providing a versatile strategy for advanced electrocatalysts in green hydrogen production.