Self-supported N-doped amorphous C layers encapsulated Mo₂C nanocrystals for efficient alkaline seawater hydrogen evolution reaction

The electrolysis of seawater for hydrogen production holds promising development prospects. However, the activity and stability of catalysts face significant challenges due to the toxicity of Cl⁻ in seawater. Herein, we demonstrate a lamellar Mo₂C electrocatalyst encapsulated in N-doped amorphous carbon layers, synthesized in situ on carbon cloth (Mo₂C@NC/CC) via carbothermal shock and chemical vapor deposition method. Experimental and theoretical results show that the heterogeneous interface between the N-doped carbon layers and Mo₂C provides abundant active sites with suitable hydrogen adsorption free energy ΔG_H*. The strong bonding between the self-supported substrate and the catalyst enhances the mechanical stability of the catalyst, while the N-doped amorphous carbon layers prevent Cl⁻ poisoning of the catalyst. The resulting Mo₂C@NC/CC exhibits superior performance for the hydrogen evolution reaction (HER) in simulated seawater (1 M KOH + seawater), achieving current densities of 10 and 100 mA cm⁻² at overpotentials as low as 94 mV and 151 mV, respectively. And it exhibits high stability for 2900 h at 10 mA cm⁻². These findings of this study offer insights for developing catalysts with enhanced stability in seawater.