Electrocatalytic performance of hetrostructured MoS2/Ag2S/Ag nanocomposites for hydrogen evolution reaction

Abstract

Two-dimensional transition metal dichalcogenides and their composites are currently being developed for use as electrocatalysts. MoS2 and Ag2S are transition metal dichalcogenides that provide electrocatalytically active edge sites for the hydrogen evolution reaction (HER). Lower electrical conductivity, on the other hand, is an issue for both MoS2 and Ag2S. To increase their electrical conductivity, Ag is employed, and hybrid MoS2/Ag2S/Ag nanostructures are hydrothermally synthesized at various temperatures (160 °C, 170 °C, 180 °C, 190 °C, and 200 °C). The samples synthesized at 180 °C, 190 °C, and 200 °C, respectively, exhibited crystallinity, lower bandgap values, increased current density at bias voltages in forward and reverse biassing, and efficient electrocatalytic activity in the HER. The nanocomposite prepared at 200 °C exhibits excellent electrocatalytic performance for the HER in acidic solution, with an overpotential of 101 mV (vs. RHE) at a current density of 10 mA/cm2, a low Tafel slope of 41 mV/dec, a large active surface area, a minimum charge-transfer resistance of 41 Ω, and long-term stability. This excellent electrocatalytic performance for HER originates from the synergistic effect of MoS2 and Ag2S components with their electrocatalytically active edge sites and highly conductive Ag nanoparticles. The results give a prominent viewpoint for the hybrid MoS2/Ag2S/Ag nanocomposite as an efficient electrocatalyst for the production of hydrogen through a water-splitting reaction.