Constructing Mono-/Di-/Tri-Types of Active Sites in MoS2 Film toward Understand Their Electrocatalytic Activity for the Hydrogen Evolution

The availability and catalytic activity of the cost-efficient electrocatalysts are the dominant factors for the hydrogen evolution reaction (HER) performance in the renewable hydrogen economy. Extensive efforts have been devoted to maximize the amount of various active sites in non-noble metal electrocatalysts for HER. This work reported a physically-sputtering strategy to construct porous and ordered 2H-MoS2 films with mono-/di-/tri-types of active sites via controlling the film thickness (from ~15 nm to 3050 nm) in the energetic plasma. As the pure (2H-) MoS2 for HER electrocatalyst, the as-fabricated 3050 nm additive-free columnar film electrode shows a stable electrochemical activity for HER (an overpotential of 204 mV at a current density of -10 mA/cm2). Interestingly, the MoS2 film with controllable thickness can serve as an innovative platform to study the electrocatalytic activity of the customized different active sites (the exposed active edge of sheets (eE), stepped-termination surfaces (sS) an...