Enhanced industrial dye degradation using Co doped in chemically exfoliated MoS₂ nanosheets

Cobalt concentrations of 7.5 and 10 wt% were incorporated in chemically exfoliated molybdenum disulfide (MoS₂) nanosheets using hydrothermal route. Various characterization techniques were employed to evaluate the Co-doped MoS₂ for structural, physiochemical, optical, and morphological properties. X-ray diffraction (XRD) technique confirmed the increase in crystallinity and crystallite size with doping ratios. The presence of functional groups and vibrational characteristic peak of Mo–O was determined using Fourier-transform infrared spectroscopy (FTIR). Field emission scanning electron microscope (FESEM) and high-resolution transmission electron microscope (HR-TEM) micrographs showed surface morphology and interlayer spacing. Absorption spectra and bandgap energy decreased with conjugation of Co ascribed to quantum confinement and edge effects as investigated using UV–visible spectroscopy. Thermal properties of prepared samples depicted weight and thermal stability as confirmed by differential scanning calorimeter and thermogravimetric analysis (DSC-TGA). Photoluminescence (PL) spectra confirmed the presence of doped species and revealed the growth of MoS₂ monolayer. Dye degradation of doped and undoped MoS₂ was tested in the presence of catalyst sodium borohydride (NaBH₄) and it was observed that the methylene blue (MB) removal process increased with doping concentration. These nanocatalysts may prove useful in the removal of industrial contaminants, especially leather, and tanneries pollutants.