N-doped Ni-Mo based sulfides for high-efficiency and stable hydrogen evolution reaction

Transition-metal sulfides (TMS) have been widely studied for electrocatalytic hydrogen evolution reaction (HER). Nevertheless, the HER activity is still far lower than the benchmark Pt-based materials due to the sparse exposed active sites, poor electron transfer and unsatisfying stability of TMS. In this work, we have successfully prepared N-doped Ni-Mo based sulfide cuboid arrays on Ni foam (denoted as N-NiMoS) towards high-efficiency and long-term HER. Systematic investigations confirm that N doping effectively regulates the electron density and tunes d-band center of NiMoS, which facilitate electron transport and improve electronic conductivity. Additionally, the hierarchical N-NiMoS cuboid arrays present larger surface area with more exposed active sites, thus endowing our catalyst with excellent HER catalytic activity with low overpotentials of 68, 250, and 322 mV at current densities of 10, 500, and 1000 mA cm−2, respectively. Impressively, the N-NiMoS electrode also displays superior stability, with a unattenuated current density over 1000-h HER operation.