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

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.