Enhancement photocatalytic activity of spinel oxide (Co, Ni)₃O₄ by combination with carbon nanotubes

In this study, some types of composites consisting of multi-walled carbon nanotubes (MWCNTs) and spinel oxide (Co, Ni)₃O₄ were synthesized by simple evaporation method. These composites were characterized by UV–Vis diffuse reflectance spectroscopy, X-rays diffraction(XRD), Scanning electron microscopy (SEM) and specific surface area(S_BET). The photocatalytic activity of the prepared composites was investigated by the following removal of Bismarck brown G (BBG) dye from its aqueous solutions. The obtained results showed that using MWCNTs in combination with spinel oxide to produced composites (spinel/MWCNTs) which succeeded in increasing the activity of spinel oxide and exhibited higher photocatalytic activity than spinel oxide alone. Also it was found that, multiwalled carbon nanotubes were successful in increasing the adsorption and improving the activity of photocatalytic degradation of Bismarck brown G dye(BBG). The obtained results showed that spinel/MWCNTs was more active in dye removal in comparison with each of spinel oxide and MWCNTs alone under the same reaction conditions. Also band gap energies for the prepared composites showed lower values in comparison with neat spinel. This point represents a promising observation as these composites can be excited using a lower energy radiation sources.