Abstract

Hydrazine (N 2H 4)-assisted hydrogen (H 2) production offers an energy-efficient alternative to conventional water electrolysis. However, developing bifunctional electrocatalysts with high electrocatalytic activity at industrially relevant current densities remains a notable challenge.

Herein, we rationally design and synthesize iridium nanocluster–incorporated MoC embedded in a N-doped C matrix (Ir NC/MoC@NC) via self-polymerization and pulsed laser irradiation in liquids (PLIL) process. The PLIL technique plays a dual role in enhancing the crystallinity of MoC and selectively enriching pyridinic-N species, thereby enabling structural defect engineering to produce a robust bifunctional catalyst for both the hydrogen evolution and hydrazine oxidation reactions (HER and HzOR) under alkaline environments. The Ir NC/MoC@NC catalyst exhibits exceptional HER performance, requiring overpotentials (η) of only 25 and 123 mV to accomplish 10 and 50 mA cm −2 , respectively, outperforming Pt/C (43 and 168 mV). For the HzOR, the catalyst delivers an ultralow η of 338 mV with a high mass activity of 133.6 A g −1 , ranking among the most active reported catalysts. Postoperational structural analysis reveals interfacial electronic polarization rather than covalent bonding, confirming dynamic charge redistribution at the Mo– Ir–N interface. A symmetric Ir NC/MoC@NC||Ir NC/MoC@NC electrolyzer enables overall N 2H 4

splitting with cell voltages of 0.08 and 0.31 V at 10 and 50 mA cm −2 , achieving ~95% N 2H 4

utilization and remarkable 100-h durability. These findings highlight defect engineering as a versatile design paradigm and establish that interfacial polarization, pyridinic-N–mediated charge redistribution, and nanocluster stabilization extend beyond Ir NC/MoC@NC, offering a generalizable strategy for next-generation bifunctional catalysts for sustainable energy conversion.