study of structure, morphology, optical absorption, and gap modulation of activated carbon (ac) / nio, fe3o4, and co3o4 oxide nanocomposites

In this paper, the synthesis and structural and optical properties of activated carbon /metal oxide nanocomposites have been studied for energy storage applications. activated carbon / nickel oxide, activated carbon / iron oxide, and activated carbon / cobalt oxide nanocomposites were synthesized by green synthesis from carbonaceous waste and their structural and optical properties were investigated. the prepared nanocomposites were characterized by x-ray diffraction (xrd), uv-vis optical absorption spectroscopy, scanning electron microscopy (sem), transmission electron microscopy (tem), and fourier-transform infrared (ftir) spectroscopy techniques. the xrd results of the activated carbon / metal oxide nanocomposites, in addition to the activated carbon background, show a polycrystalline phase corresponding to nio, fe3o4, and co3o4 oxides. according to sem images, a carbon porous background was observed in nanocomposites, which is filled with metal oxide nanoparticles and these nanoparticles present on its surface non-uniformly. the band gap results of nanocomposites showed the presence of two shoulders clearly indicating the presence of two components in the nanocomposite, i.e., activated carbon (3.62-4.65 ev) and metal oxide (3.0 ev- 4.25 ev). in ftir analysis, in addition of the carbon-carbon bonds, specific peaks were observed in the range of k=400-700 cm-1, indicating that ac/ metal oxide nanocomposites have been successfully synthesized.