Epitaxial MoS2 nanosheets on nitrogen doped graphite foam as a 3D electrode for highly efficient electrochemical hydrogen evolution

Hydrogen evolution reaction (HER) electrocatalysts are crucial to the application of renewable energy. In this study, the interactive MoS2 nanosheets uniformly grown on nitrogen-doped graphite foam (MoS2/NGF) are obtained via a facile solvothermal synthesis method. The resulting MoS2/NGF shows excellent catalytic activity for HER performance, which exhibits low onset potential of 12 mV versus reversible hydrogen electrode (RHE), low overpotential of 35 mV at 10 mA cm(-2), and outstanding stability over 3000 cycles under acidic conditions. The results reveal that mixture of different oxidation degrees of the graphite foam bring in surface defects, which promote the epitaxial growth of MoS2 nanosheets on the outer graphene layer with more defects. These defects induce a synergistic effect and contribute to the HER process. Further experiments on the effect of oxidation degree of graphite foam on the HER performance for the MoS2/NGF composites confirmed that there is an optimum condition for the catalytic activity of HER due to the internal conductive channels provided by graphite foam. The HER performance of MoS2/NGF is superior to most of the reported MoS2-based catalysts, especially its onset potential and the exchange current density. (C) 2018 Elsevier Ltd. All rights reserved.