Photocatalytic degradation of methylene blue dye and magneto-optical studies of magnetically recyclable spinel NixMn1-xFe2O4 (x = 0.0–1.0) nanoparticles

Abstract

Nickel doped spinel manganese ferrite (NixMn1-xFe2O4: x = 0.0–1.0) nanoparticles were prepared successfully by a superficial microwave irradiation technique using urea as the fuel. Powder X-ray diffraction (XRD) analysis was recognized the configuration of single phase spinel structure of NixMn1-xFe2O4. Debye Sherrer's formula was used to calculate the average crystallite size of the samples, which were found in the range of 15–20 nm. High resolution scanning electron microscopy (HR-SEM) was used to analyze the surface morphology of the samples, which showed the particle like-morphology with smaller agglomeration, and it was also confirmed by high resolution transmission electron microscopy (HR-TEM). Energy dispersive X-ray (EDX) analysis confirmed the elemental composition, which also evidence for the formation of single pure phase. Microwave heating method produced well crystalline nature of the products, which was confirmed by selected area electron diffraction (SAED) analysis. UV–Visible diffuse reflectance spectra (DRS) were used to calculate the energy band gap and the observed values are increased slightly from 2.05 eV to 2.44 eV with increasing the Ni-dapant. Magnetic characterization of the samples were analyzed by room temperature vibrating sample magnetometer (VSM) technique and the observed magnetization (Ms) values are decreased with increasing Ni content, due to the different magnetic moments of Mn2+ and Ni2+ cations. Photocatalytic degradation (PCD) of methylene blue dye was carried out by self designed photo-catalytic reactor. It was observed that PCD efficiency is increased with increase in concentration of Ni and the sample Ni0.6Mn0.4Fe2O4 shows better photocatalytic activity (96.73%) than other samples.