Sulfurized Co-Mo Alloy Thin Films as Efficient Electrocatalysts for Hydrogen Evolution Reaction

Here, we successfully fabricated sulfurized Co-Mo alloy thin film electrodes with different compositions and studied their catalytic properties for hydrogen evolution reaction (HER). The resulting alloy films surpass the HER activity of the MoS2 counterpart, whose electronic states and morphology are modified by the Co atoms, leading to enhanced HER activity. The best performing electrode at 23 at.% Co concentration exhibits a 272 mV lower overpotential than the MoS2 film at 10 mA cm−2 current density and a Tafel slope of 62 mV dec−1. Combined with the good stability, the sulfurized Co–Mo alloy thin films are promising catalysts for the electrocatalytic HER in acidic solution.