Boosting electrochemical hydrogen evolution activity of MoS2 nanosheets via facile decoration of Au overlayer

Abstract

--Owing to its unique physicochemical properties, two-dimensional (2D) layered MoS2 has been proposed as a potential catalyst for efficient hydrogen evolution reaction (HER). However, their large-scale application is still hindered due to limited active sites, poor conductivity, and restacking during synthesis. Herein, we report a one-step hydrothermal route to grow MoS2 nanosheets on molybdenum (Mo) foil substrate followed by Au decoration as an active cocatalyst to enhance the HER performance of MoS2 nanosheets. A facile, quick, and controlled decoration of stable Au overlayer with different mass loadings was performed using a sputtering Au coating unit for different deposition times (10s, 30s, and 50s), thus paving the way for producing efficient and inexpensive HER electrocatalysts. Electrochemical studies of different Au–MoS2/Mo hybrids demonstrate that the optimized Au–MoS2/Mo-30s sample exhibits ultralow onset potential (52 ± 2 mV vs. RHE), small overpotentials of 136 ± 6 and 318 ± 3 mV (vs. RHE) at current densities of 10 and 100 mA cm−2, a small Tafel slope (46.23 ± 6 mV/dec), along with an outstanding electrochemical stability over a couple of days. Presence of metallic 1T-phase of MoS2, as well as the synergistic effect between MoS2 and Au, result in enhanced electrical conductivity, high density of active sites, large electrochemically accessible surface area, and fast charge transfer at the catalyst-electrolyte interface for boosting HER activity of the hybrid catalyst.