A combined experimental and theoretical study on the structural, optical and electronic properties of hetero interface-functionalized MoS2 /Co3O4 nanocomposite

Abstract

Co3O4 decorated MoS2 nanoflower (MoS2/Co3O4) has been successfully synthesized by a simple hydrothermal method. A combined experimental and theoretical investigation was performed to comprehend the effect of Co3O4 on the structural, optical, and electronic properties of MoS2 nanoflowers. A number of characterization techniques have been used to study the surface morphologies, structural properties, chemical constitution, and optical properties of the nanocomposites including, FE-SEM, TEM, XRD, XPS, and UV–VIS spectroscopy. Flower-like structures of MoS2 and MoS2/Co3O4 have been observed from the FE-SEM and TEM images. The Rietveld refinement of the X-ray diffraction (XRD) pattern was used to estimate the various structural parameters of the nanoflowers which also confirms the phase purity of the MoS2 nanoflower. X-ray photoelectron spectroscopy (XPS) results revealed strong electronic interaction between Mo–S and Co–O in the nanocomposites. The optical bandgap of the as-prepared samples was estimated using diffusive reflectance spectra and was found to be varied between 1.44 eV to 1.27 eV nanostructure due to the incorporation of Co3O4 nanoparticle. To fully understand and validate the structural, optical, and electrical characteristics of the samples, density functional theory (DFT) calculations were carried out. DFT results revealed that the Mo-4d and Co-3d orbital-orbital interactions occur due to the incorporation of Co3O4 into MoS2, leading to a decrease in the band gap. Moreover, a charge redistribution occurred between MoS2 and Co3O4 interface, creating more active sites for electro and opto-catalytic reactions. Among the results, the red shift of the optical absorbance spectra is the most obvious one enabling our synthesized nanocomposite to absorb in the near-infrared range. This study will offer a new insight into the fabrication of transition oxide-based hetero-interface influenced MoS2 functional devices for diverse applications.