Dual-function efficient hydrogen evolution reaction electrocatalyst and electrode material for supercapacitors based on ternary composite FeS2/Fe2O3/MoS2 nanostructures

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Hydrogen is a promising and environment-friendly energy source that can be produced in a highly efficient manner through water electrolysis. This process requires the use of effective electrocatalysts to facilitate the hydrogen evolution reaction (HER). In this study, the synthesis, characterization, and electrochemical performance of FeS2, Fe2O3, a binary composite of FeS2 and Fe2O3 (FeS2/Fe2O3), and a ternary composite of FeS2, Fe2O3, and MoS2 (FeS2/Fe2O3/MoS2) are investigated. The materials were prepared using a hydrothermal technique and analyzed using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–Vis) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and electrochemical assessments. The ternary composite demonstrated improved HER performance, with the FeS2/Fe2O3/MoS2 hybrid exhibiting the highest electrochemically active surface area ECSA (27.79 μF/cm2), and lowest charge transfer resistance Rct (288 Ω), overpotential (96 mV vs. SHE at 10 mA/cm2) and Tafel slope (72 mV/decade), indicating the superior performance of the ternary composite in facilitating the HER. These results indicate that the combination of MoS2 with FeS2 and Fe2O3 greatly enhances the catalytic activity, making the ternary composite a highly attractive option for effective water-splitting applications. In addition, the hybrid composite exhibited outstanding supercapacitor performance, with a specific capacitance of 171.42 F/g at a current density of 1 A/g. These results indicate that FeS2/Fe2O3/MoS2 can function as a highly effective electrocatalyst for the HER and is a superior material for supercapacitors.