Stabilizing Active Edge Sites in Semicrystalline Molybdenum Sulfide by Anchorage on Nitrogen-Doped Carbon Nanotubes for Hydrogen Evolution Reaction

Finding an abundant and cost-effective electrocatalyst for the hydrogen evolution reaction (HER) is crucial for a global production of hydrogen from water electrolysis. This work reports an exceptionally large surface area hybrid catalyst electrode comprising semicrystalline molybdenum sulfide (MoS2+x) catalyst attached on a substrate based on nitrogen-doped carbon nanotubes (N-CNTs), which are directly grown on carbon fiber paper (CP). It is shown here that nitrogen-doping of the carbon nanotubes improves the anchoring of MoS2+x catalyst compared to undoped carbon nanotubes and concurrently stabilizes a semicrystalline structure of MoS2+x with a high exposure of active sites for HER. The well-connected constituents of the hybrid catalyst are shown to facilitate electron transport and as a result of the good attributes, the MoS2+x/N-CNT/CP electrode exhibits an onset potential of -135 mV for HER in 0.5 M H2SO4, a Tafel slope of 36 mV dec(-1), and high stability at a current density of -10 mA cm(-2).