Manganese spinel ferrite-reduced graphene oxides nanocomposites for enhanced solar irradiated catalytic studies

Abstract An excellent photocatalyst must have narrow band gap value, broad absorption range and high electrical conductivity. The co-precipitation route was followed to synthesize copper substituted manganese ferrite nanoparticles because the co-precipitation is a facile, short and easy to handle method. The nanocomposite of copper substituted manganese ferrite with rGO was synthesized by sonication method. The graphene was used for composite synthesis because of its extraordinary properties such as chemical stability, high transparency, large surface area, high electron transfer ability. Graphene can also improve catalytic acitivity of spinal ferrites. X-ray diffraction (XRD), Raman spectroscopy, and field emission scanning electron microscopy (FESEM) were employed to confirm the structural, spectral and morphological aspects of prepared nanomaterials and their composites with rGO. XRD confirmed face centered cubic (FCC) crystal structure. The appearance of relative broad peaks estimated the formation of nanocrystalline size of synthesized samples. SEM images showed that the nanoparticles have spherical morphology. Furthermore, rGO sheets can be clearly seen in SEM images of composite material. It was investigated that electrical conductivity of MnF2O4 was increased by the substitution of metal cations such as copper. Current – voltage measurements were carried out at room temperature and confirmed the enhanced conductivities of copper doped manganese ferrite and its rGO based nanocomposite. These photocatalysts were used for the degradation of methylene blue (MB) dye and Mn0.9Cu0.1Fe2O4/rGO nanocomposite showed great activity in photocatalysis experiment with 77% degradation efficiency. This increment in photocatalysis was found to be due to synergistic effect of ferrite material and rGO sheets, which increases the electrical conductivity and decreases the photoexcited electrons-holes pair recombination of composite materials.