Atom-Efficient Ir Nanoclusters in Laser-Engineered MoC@N-Carbon for Ultralow-Overpotential Hydrogen Evolution

Abstract

Herein, we rationally design and synthesize iridium nanocluster-incorporated MoC embedded in a N-doped C matrix (IrNC/MoC@NC) via self-polymerization and pulsed laser irradiation in liquids (PLIL) process. The PLIL process simultaneously enhances the crystallinity of MoC and enriches pyridinic-N defects, thereby enabling effective interfacial defect engineering. As a result, IrNC/MoC@NC exhibits outstanding bifunctional electrocatalytic performance in alkaline media, delivering ultralow overpotentials (eta) of 25 and 123 mV for the hydrogen evolution reaction at 10 and 50 mA cm-2, respectively, significantly outperforming commercial Pt/C (43 and 168 mV). For the hydrazine (N2H4) oxidation reaction (HzOR), the catalyst achieves a low eta of 338 mV along with a high mass activity of 133.6 A g-1, ranking it among the most active catalysts reported to date. Post-operational structural analyses, corroborated by in situ Raman spectroscopy and theoretical calculations, reveal that the enhanced catalytic performance originates from interfacial electronic polarization rather than the formation of covalent bonding, confirming dynamic charge redistribution at the Mo-Ir-N interface. A symmetric IrNC/MoC@NC||IrNC/MoC@NC electrolyzer enables overall N2H4 splitting with cell voltages of 0.08 and 0.31 V at 10 and 50 mA cm-2, achieving similar to 95% N2H4 utilization and remarkable 100-h durability.