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.