Synthesis of a MoS _x -O-PtO _x Electrocatalyst with High Hydrogen Evolution Activity Using a Sacrificial Counter-Electrode

Water splitting is considered to be a very promising alternative to greenly produce hydrogen, and the key to optimizing this process is the development of suitable electrocatalysts. Here, a sacrificial-counter-electrode method to synthesize a MoS _x /carbon nanotubes/Pt catalyst (0.55 wt% Pt loading) is developed, which exhibits a low overpotential of 25 mV at a current density of 10 mA cm^-2, a low Tafel slope of 27 mV dec^-1, and excellent stability under acidic conditions. The theory calculations and experimental results confirm the high hydrogen evolution activity that is likely due to the fact that the S atoms in MoS _x can be substituted with O atoms during a potential cycling process when using Pt as a counter-electrode, where the O atoms act as bridges between the catalytic PtO _x particles and the MoS _x support to generate a MoS _x -O-PtO _x structure, allowing the Pt atoms to donate more electrons thus facilitating the hydrogen evolution reaction process.