▎ 摘　　要

Facile design of low-cost and highly active catalysts from earth-abundant elements is favorable for the industrial application of water splitting. Here, a simple strategy to synthesize an ultrathin molybdenum disulfide/nitrogen-doped reduced graphene oxide (MoS2/N-RGO-180) nanocomposite with the enlarged interlayer spacing of 9.5 angstrom by a one-step hydrothermal method is reported. The synergistic effects between the layered MoS2 nanosheets and N-doped RGO films contribute to the high activity for hydrogen evolution reaction (HER). MoS2 /N-RGO-180 exhibits the excellent catalytic activity with a low onset potential of -5 mV versus reversible hydrogen elelctrode (RHE), a small Tafel slope of 41.3 mV dec(-1), a high exchange current density of 7.4 x 10(-4) A cm(-2), and good stability over 5 000 cycles under acidic conditions. The HER performance of MoS2 /N-RGO-180 nanocomposite is superior to the most reported MoS2-based catalysts, especially its onset potential and exchange current density. In this work, a novel and simple method to the preparation of low-cost MoS2-based electrocatalysts with the extraordinary HER performance is presented.