Simultaneous Phase and Electronic Structure Regulation of MoC via B,N-Doping and Bimetallic Synergy for Efficient Hydrogen Evolution

Abstract

Molybdenum carbide (MoxC) has emerged as a promising electrocatalyst for the hydrogen evolution reaction (HER), attributed to its low cost and platinum-like electronic structure.However, its catalytic performance is often hindered by three critical challenges: suboptimal hydrogen adsorption free energy, the tendency of nanoparticles to agglomerate, and insufficient stability in acidic media. To simultaneously address these bottlenecks, this study reports a molten salt-assisted pyrolysis strategy utilizing POM@ZIF precursors to synthesize cobaltnickel bimetallic modified MoxC nanocrystals encapsulated within a boron and nitrogen codoped carbon matrix (Co,Ni-MoC@BNC). Boron doping not only induces the formation of a metastable, highly conductive MoC phase but also facilitates the efficient reduction of Co/Ni species, thereby generating significant synergistic effects with the bimetallic components. The resulting catalyst exhibits superior HER activity and stability in 0.5 M H2SO4 , delivering a low overpotential of 127 mV at a current density of 10 mA cm-2 and sustaining stable operation for 30 hours at 15 mA cm-2 . Notably, it outperforms commercial 10% Pt/C catalysts in the high current density region. Density functional theory calculations further confirm that the hybridization between Co d-orbitals and C p-orbitals, combined with the electronic modulation from B-doping, synergistically optimizes the Gibbs free energy of hydrogen adsorption (ΔGH* = 0.21 eV), approaching the ideal value of 0 eV. This work offers new insights into the design of high-performance non-noble metal-doped Mo-based HER electrocatalysts by demonstrating a multi-component synergistic strategy to precisely modulate the crystalline phase and electronic structure of MoxC.