Operando-regulated charge-transfer kinetics in biomass-derived Ni–Mo/N-doped graphitic carbon for hydrazine-assisted seawater electrolysis

Hydrazine-assisted electrolysis provides an energy-efficient route for hydrogen production by replacing the sluggish oxygen evolution reaction and mitigating chloride-induced parasitic reactions in seawater. Herein, we develop a bimetallic nickel–molybdenum incorporated nitrogen-doped graphitic carbon (NiMo@NGC) electrocatalyst as a non-noble platform for alkaline hydrogen evolution coupled with hydrazine oxidation in seawater. Hydrazine is employed as a kinetic probe to decouple anodic charge-transfer processes from oxygen evolution pathways. Operando electrochemical impedance spectroscopy reveals a transition to charge-transfer-dominated anodic kinetics driven by Ni–Mo interaction within the conductive N-doped carbon matrix. As a result, NiMo@NGC exhibits low charge-transfer resistance, and stable performance under alkaline and seawater conditions. A symmetric NiMo@NGC||NiMo@NGC electrolyzer delivers a low cell voltage of 0.45 V for hydrazine-assisted seawater electrolysis and maintains stable operation. Post-electrolysis analyses confirm preserved framework integrity with mild surface reconstruction. This work establishes an operando-guided strategy for designing non-noble electrocatalysts for low-energy, seawater-tolerant hydrogen production.