Fabricated Au NPs/MoS2@rGO multidimensional hybrid photocatalyst for enhanced H2 evaluation reaction performance under UV light

In the present study, we report the synthesis of Au nanoparticles (Au NPs) on molybdenum sulfide@reduced graphene oxide (MoS2@rGO)-based hetero-photocatalytic nanohybrids through a one pot hydrothermal method. Variety of characterization was performed to support this hypothesis including X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectra (XPS), Raman, Ultra violet, photoluminescence and N2 adsorption analysis. BET surface area and BJH pore size of Au/MoS2@rGO was found to be 128 m2g−1 and 10.5 nm, which is higher than bare MoS2 (43 m2/g and 3.5 nm). Electrochemical impedance spectroscopy (EIS) results indicate that Au/MoS2@rGO performed a faster charge-transfer in comparison to MoS2@rGO hybrid. The calculated optical bandgap values are 2.78, 2.51 and 2.23 eV for MoS2, MoS2@rGO and Au/MoS2@rGO composite samples, respectively. Moreover, the lowest PL intensity of Au/MoS2@rGO indicates that less recombination of electron-hole pair and can be useful for the generation of H2 activity under light illumination. Furthermore, the resulting Au/MoS2@rGO catalyst has a reduced overpotential of 60 mV and a low Tafel slope of 32 mV decade−1, indicating increased electrocatalytic activity towards HER. The improved performance is attributed to the increased active sites and a synergistic effect between Au and molybdenum, leading to electronic structure change and charge redistribution of MoS2. The results provide a low-cost countermeasure for the preparation of rGO-supported MoS2 catalysts, and have broad application prospects.