In Situ Engineering of Double-Phase Interface in Mo/Mo₂C Heteronanosheets for Boosted Hydrogen Evolution Reaction

Two-dimensional Mo/Mo 2 C heteronanosheets (Mo/Mo 2 C-HNS) were successfully prepared via a NaCl template-assisted synthesis route followed by a controllable simultaneous reduction and carbonization of MoO 3 nanosheets for efficient hydrogen evolution reaction (HER) catalysis under both acidic and alkaline conditions. The Mo species in the atomically thin Mo/Mo 2 C-HNS not only guarantees the rapid transport of electrons but also optimizes the electronic configuration of β-Mo 2 C. Besides, the abundant Mo/β-Mo 2 C heterointerfaces in nanodimension afford large numbers of additional heterogeneous catalytic sites. HER electrocatalytic performance with overpotential of merely 89 mV to drive a current density of 10 mA/cm 2 in 0.5 M H 2 SO 4 is therefore achieved. Strikingly, stable chronoamperometric electrolysis for 20 h and also an impressive cycling stability with negligible overpotential decay over 4000 sweeps demonstrate its considerable durability in an acidic environment. These findings highlight the promising potential of Mo/Mo 2 C-HNS catalyst as an efficient and stable noble metal-free electrocatalyst toward the HER.