Paragenesis of Mo2C nanocrystals in mesoporous carbon nanofibers for electrocatalytic hydrogen evolution

Abstract Cost-effective Mo 2 C nanocrystals homogeneously distributed in interconnected mesoporous carbon nanofibers are prepared through an electrospinning route combined with a subsequent pyrolysis process. The crystal phases of the Mo 2 C nanocrystals are controllable and their phase-dependent electrocatalytic activities for the hydrogen evolution reaction (HER) are explored. The nanocomposite catalyst made of the hexagonal-phase Mo 2 C nanocrystals in carbon nanofibers exhibits outstanding electrocatalytic kinetics and high activities for the HER in both acidic and basic media. It is found that the overpotentials are 160 mV in 0.5 M H 2 SO 4 and 92 mV in 1 M KOH at a current density of 10 mA cm −2 . The Tafel slopes of 66 mV dec −1 in 0.5 M H 2 SO 4 and 63 mV dec −1 in 1 M KOH are achieved. Also, the as-obtained Mo 2 C/C electrocatalyst shows long-term durability.