Electrodeposited Mo₃S₁₃ Films from (NH₄)₂Mo₃S₁₃·2H₂O for Electrocatalysis of Hydrogen Evolution Reaction

Molybdenum sulfides are considered to be one kind of the promising candidates as cheap and efficient electrocatalysts for hydrogen evolution reaction (HER). But this is still a gap on electrocatalytic performance toward Pt. To further enhance electrocatalytic activity of molybdenum sulfides, in this work, we prepared Mo₃S₁₃ films with high ratio of sulfur to molybdenum by electrodeposition. The Mo₃S₁₃ films exhibit highly efficient electrocatalytic activity for HER and achieve a current density of 10 mA/cm² at an overpotential of 200 mV with an onset potential of 130 mV vs RHE and a Tafel slope of 37 mV/dec, which is superior to other reported MoS₂ films. The highly electrocatalytic activity is attributed to high percentage of bridging S₂^2- and apical S^2- as well as good conductivity. This study provides an avenue for designing new molybdenum sulfides electrocatalysts.