Two steps hydrothermal synthesis of MoS2 - ZnO hybrid for the enhancement in electrocatalytic hydrogen evolution reaction

Abstract

The present work reports the successful synthesis of MoS₂–ZnO hybrid using a two-step hydrothermal method. The properties of the synthesized samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopes (FESEM), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared (FTIR) and energy-dispersive x-ray (EDX) analysis.

FESEM results confirmed the successful synthesis of the MoS₂–ZnO hybrids. XRD analysis indicated high crystallinity and purity of the MoS₂–ZnO composites. The oxidation states of the different elements in the hybrid sample were confirmed from the XPS study.

The synthesized hybrid sample showed promise for its use as an electro-catalyst during the evolution of hydrogen by hydrogen evolution reaction (HER), which is much better compared to both the pure MoS₂ and ZnO. The betterment has been confirmed from the linear sweep voltammetry that showed the hybrid exhibited a high exchange current density, whereas the values of overpotential for pure MoS₂, ZnO, and hybrid, respectively, came as 428, 427, and 420 mV. Additionally, the small Tafel slope of 283 mV/dec for the hybrid sample indicates its efficiency as an electrocatalyst for practical HER applications. The least value of onset potential (−0.111 V) for the hybrid sample also supports the above claim.