• • Overpotential of 34 mV at 10 mA cm−2 in alkaline media: This value approaches the thermodynamic limit for HER and outperforms commercial Pt/C in alkaline conditions, reducing electrical energy consumption by approximately 15% compared to standard Ru-based catalysts, directly lowering hydrogen production costs.
• • Operational stability for 200 h at 10 mA cm−2 with Faradaic efficiency >97%: The catalyst maintains structural integrity and activity over 200 h, exceeding typical single-atom catalyst lifetimes by an order of magnitude, which is critical for continuous industrial electrolyzer operation and minimizing downtime for catalyst replacement.
• • Sub-1 nm Ru clusters and single atoms on amorphous FeMoSx: The coexistence of atomic and sub-nanometer Ru species creates synergistic active sites that facilitate both hydrogen adsorption and hydroxyl desorption, addressing the multistep kinetic bottleneck in alkaline HER and enabling a 2-fold increase in turnover frequency relative to Ru single-atom-only catalysts.
• • Shortened Mo–S and Fe–S bond lengths: The amorphous structure induces lattice strain that shortens metal–sulfur bonds by approximately 0.05 Å, as confirmed by EXAFS, which optimizes the electronic environment of Ru and lowers the hydrogen adsorption free energy (ΔG_H*) to near-zero, enhancing intrinsic activity.