Electrocatalytic HER: Electrodeposition of PdPt nanoparticles onto the S-vacant molybdenum disulfide nanosheets, which were pre-treated using exfoliation, created a catalyst with a lower Tafel slope and a 1.7× higher mass activity towards the hydrogen evolution reaction (HER) at an overpotential of 20 mV, outperforming a commercial Pt/C catalyst.

Abstract

Deposition of metal nanoparticles onto the molybdenum disulfide (MoS₂) nanosheets is an efficient method to tune the electronic structure of the MoS₂ and maximize its catalytic performance towards the hydrogen evolution reaction (HER). Herein, we report the electrodeposition of Pd and Pt nanoparticles onto desulfurized MoS₂ nanosheets (MoS_2–x) to achieve an improved HER activity in an acidic electrolyte. The initial MoS₂ powder was exfoliated and isolated through centrifugation, followed by electrochemical desulfurization to create defect sites. Subsequently, Pt and Pd nanoparticles were electrodeposited onto the S-vacancies of MoS_2–x nanosheets. The resulting PdPt nanoparticles, with a diameter of 3.3 ±1.7 nm, were distributed across the surfaces of the nanosheets. A preferential deposition was evident at the edges of the nanosheets, particularly when Pd was deposited first followed by Pt. Owing to this preferential deposition of Pd and Pt and the synergistic interaction of MoS_2–x with Pd and Pt, the prepared catalyst exhibited a low overpotential of 30 mV at 10 mA cm⁻², which is 2.7× lower than the MoS_2–x alone. The prepared catalyst exhibited a 1.7× increase in the mass activity at 20 mV overpotential, relative to that of a commercial Pt/C nanocatalyst, showcasing its promising potential as an alternative catalyst.