Porous nanoMoC@graphite shell derived from a MOFs-directed strategy: an efficient electrocatalyst for the hydrogen evolution reaction

The hydrogen evolution reaction using noble-metal free electrocatalysts has captured increasing attention due to its importance in renewable hydrogen production. Herein, a highly active and stable electrocatalyst of MoC encapsulated by graphitized carbon shells (nanoMoC@GS) has been developed via an in situ carburization of a Mo-based metal-organic framework (Mo-MOF) with the atomic periodic structure. The ultrafine MoC nanoparticles (similar to 3 nm) confined by 1-3 layered graphite shells significantly favor the efficient HER in both acidic and basic media. In particular, a low overpotential (eta(10) = 124 and 77 mV at a current density of -10 mA cm(-2)), a small Tafel slope (43 and 50 mV dec(-1)) and a high exchange current density (j(0) = 0.015 and 0.212 mA cm(-2)) are achieved on nanoMoC@GS in 0.5 M H2SO4 and 1.0 M KOH, respectively. Such remarkable activity, outperforming most current noble-metal-free electrocatalysts, stems from the cooperative/synergistic effects of ultrafine MoC nanostructure, ultrathin and conductive graphitized carbon shells, and enriched porosity. This work demonstrates a feasible way to design high-performance electrocatalysts via converting atomic contact hybrid structures (e.g., MOFs), illustrating a new perspective for developing nanocatalysts in the energy chemistry field.