Low-temperature hydrothermal growth of MoS2 nanostructures on carbon foam for hydrogen evolution reaction

Abstract

The high energy density of hydrogen as a non-pollutant energy resource has attracted more attention as a promising alternative to fossil fuels which cause global pollution and planet warming. While noble metals are employed as electrochemical catalysts in the electrolysis of water to produce hydrogen, their high cost and limited availability prevent them from being used on a larger scale. Due to its good electrochemical activity, strong acid resistance, and affordable price, two-dimensional molybdenum disulfide (2D-MoS2) is introduced as the hydrogen evolution reaction (HER) catalyst. For tackling the low electrical conductivity and low active sites of MoS2, carbon-based materials have been used as high electrical conductive supports to accommodate the well-distributed MoS2 nanostructures to exposure of the higher active sites to the water molecules. In this study, the low-cost carbon foam/MoS2 (CF/MoS2) composites were hydrothermally synthesized at low temperatures (200 °C) as an economical hydrogen generation catalyst. Furthermore, the effects of sulfur precursors are investigated on the morphology, structure, crystallinity, and HER activity by using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. The CF/MoS2 composites derived from sulfur, thiourea, thioacetamide, and sodium sulfide, display the 1T/2H crystalline phase. The sulfur-derived CF/MoS2 delivers the best HER activity with the low overpotential of 217 mV at the current density of 10 mA cm−2 and Tafel slope of 112 mV dec−1.