Molybdenum carbide interfaced with fullerene-derived curved carbon accelerates electron transfer for hydrogen...

Designing highly efficient and stable electrocatalysts with accelerated electron transfer to active sites is of critical importance for the hydrogen evolution reaction (HER). Herein, we report molybdenum carbide interfaced with fullerene (C₆₀)-derived carbon (Mo₂C/C₆₀), prepared through a direct carbothermal reduction method using C₆₀ as the carbon source. Compared with analogous catalysts prepared using commercial carbon black, graphene, and carbon nanotubes as carbon supports, the Mo₂C/C₆₀ catalyst exhibits superior HER activity, achieving a low overpotential of 45 mV at 10 mA cm^-2. Furthermore, the Mo₂C/C₆₀-based electrolyzer requires only 1.55 V to reach a current density of 10 mA cm^-2 and exhibits negligible current decay during 100 h of continuous operation at 2.2 V. This enhanced performance is associated with the structural transformation of fullerene during high-temperature treatment, in which its cage framework reconstructs into curved carbon layers. The molybdenum carbide nanoparticles are uniformly embedded within the curved carbon matrix and form intimate interfaces with the carbon framework, effectively suppressing their agglomeration and facilitating interfacial electron transfer to the active Mo₂C sites during the HER. Density functional theory (DFT) calculations further indicate that the curved carbon modulates the electronic structure of molybdenum carbide and optimizes the hydrogen adsorption free energy, thereby enhancing the intrinsic HER activity of the active Mo₂C sites. This work offers a strategy for designing efficient and stable fullerene-based non-precious-metal HER electrocatalysts.