Metallic-Phase MoS2 Nanopetals with Enhanced Electrocatalytic Activity for Hydrogen Evolution

MoS2 shows a great promise as a low-cost and highly active alternative to platinum-based catalysts for electrochemical hydrogen production from water. The activity of MoS2 is believed from the edge, defect sites, and the basal plane of metallic phase (M-MoS2). Here we report on a facile hydrothermal method for the preparation of MoS2 nanopetals that are in metallic phase and have abundant edges. The amount of sulfur precursors are found to play a critical role on the formation of MoS2 nanopetals. The MoS2 nanopetals exhibit remarkable electrocatalytic activities for the hydrogen evolution reaction (HER), with a low overpotential of 210 mV at the current density of 10 mA cm(-2) and a Tafel slope of 44 mV per decade. The MoS2 nanopetals also display very good durability, with a very small negative shift of 11 mV at the current density of 10 mA cm(-2), and negligible shift at the current density of 50 mA cm(-2) after 2000 cycles. Our facile preparation method and high electrocatalytic activity of MoS2 nanopetals for HER pave a new avenue for the development of highly efficient MoS2-based electrocatalysts for HER.