▎ 摘　　要

Molybdenum carbide (Mo2C) based electrocatalysts have been considered one of the promising candidates to replace Pt-based catalysts toward the hydrogen evolution reaction (HER). However, their practical application remains a great challenge. In this report, Mo2C nanoparticles are supported on a high-defective graphene nanospheres (GNs) synthesized by arc in liquid method. Attributing to the defect-rich features of GNs, the supported Mo2C nanoparticles with diameters of 1.87 nm exhibit a homogeneous dispersion without obvious aggregation. Accordingly, the Mo2C/GNs catalyst exhibits an improved HER activity compared to MoO2/GNs with smaller Tafel slope of 58.6 mV dec(-1) and lower overpotential of 196 mV to reach - 10 mA cm(-2), as well as excellent cycling stability. These findings present the potential to enhance the catalytic performance of Mo2C species by adopting defect-rich carbon supports. Graphic A high-defective GNs were successfully synthesized through a simple and rapid self-assembly strategy called "the arc-discharge in liquid toluene" method, and then used as the support for Mo2C without any pre-treatment. Attributing to the structural features, Mo2C nanoparticles are supported on the prepared GNs with diameters of 1.87 nm exhibit a homogeneous dispersion without obvious aggregation. In addition, the Mo2C/GNs catalyst exhibits an improved HER activity compared to Mo-2/GNs with smaller Tafel slope of 58.6 mV dec(-1) and lower overpotential of 196 mV to reach -10 mA cm(-2), as well as excellent cycling stability. These findings present the potential to enhance the catalytic performance of Mo2C species by defective carbon supports. [GRAPHICS]