Synthesis and Characterization of Graphene /MoS2 /RuO2 Ternary Nanocomposite for Hydrogen Evolution

Abstract

Hydrogen (H2) is a promising and abundant clean fuel with the potential to replace fossil fuels soon. Large-scale H2 production can be achieved through the electrocatalytic water-splitting process, which is considered an environmentally sustainable and green approach. This study systematically investigates the electrocatalytic performance of individual materials, namely graphene nanosheets (GNS), molybdenum disulfide (MoS2), ruthenium dioxide (RuO2), and their composites, that have not been previously reported in the literature, for hydrogen evolution reaction (HER) applications. The materials are synthesized using Liquid Phase Exfoliation (LPE) at 500 and 1000 RPM for both GNS and MoS2, and hydrothermal methods for RuO2 nanosheets and nanoparticles. Composites are carefully prepared to exploit synergistic effects, aiming for enhanced electrocatalytic activity and stability, which constitutes an additional novelty in this research. Characterization techniques, including Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Raman Spectroscopy, and Fourier-Transform Infrared Spectroscopy (FTIR), are employed for comprehensive evaluation. Electrochemical performance is assessed using Linear Sweep Voltammetry (LSV), Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), and stability tests. The GNS-1000/MoS2-1000/RuO2-NSs composite exhibits promising results for HER application. For example, Tafel plots highlight the composite's superior electrocatalytic performance for HER, with the lowest Tafel slope of 59 mV/dec. Polarization curves derived from LSV data demonstrate a low overpotential of 63 mV, which can be attributed to synergistic effects such as enhanced electron transfer, improved dispersion of active sites, increased surface area, and favorable electronic interactions. Further investigation of synergistic effects and HER mechanisms can provide valuable insights for designing efficient electrocatalysts for hydrogen evolution, promoting clean energy solutions.