Annealing disintegrates Cu₂MoS₄ nanosheets into MoS₂ and Cu₂S nanoheterostructures

The hydrothermal synthesis and effect of annealing temperature on morphological and structural properties of Cu₂MoS₄ nanosheets are studied in this work. The as-grown Cu₂MoS₄ nanosheets are annealed in ambient Ar environment at different temperatures (250, 300, 350, 400, 500, 750, 1000 °C). Suitable annealing disintegrates the Cu₂MoS₄ nanosheets into MoS₂ and Cu₂S nanoheterostructures. The annealing effect on prepared materials is characterized through X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The structural changes are observed during XRD analysis and corresponding morphological changes are studied through TEM. Raman spectroscopy is employed to study the vibrational modes of the materials and it also confirms the disintegration of Cu₂MoS₄ nanosheets into MoS₂ and Cu₂S nanoheterostructures. The influence of annealing temperature on binding energy of the Cu₂MoS₄ nanosheets is studied by XPS. The assembled nanoheterostructures are tested as anode material for the Li-ion battery and it shows significant specific capacity and cyclability.