Synthesis of MFe<sub>2</sub>O<sub>4</sub> (M: Cu, Mn, Co, Ni) magnetic nanoparticles and their efficient catalytic role in nitrophenol reduction
Deepshikha Gupta, Vabhika Rishi, Tejendra K. Gupta
Abstract
In this work, transition metal mixed ferrites (MFe2O4 (M: Cu, Mn, Co, Ni)) magnetic nanoparticles (MNPs) have been synthesised via co-precipitation method and annealed at 800°C. These synthesised metal ferrite MNPs were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) for their structural, surface morphological and magnetic properties, respectively. The catalytic efficiency of the synthesised ferrite MNPs was explored for the reduction of nitrophenols. Cu doped ferrite MNPs demonstrated excellent catalytic activity (more than 90% reduction) as compared to other metal mixed ferrite MNPs which may be due to the soft behaviour of Cu and better separation efficiency of the electron-hole pairs. The kinetics of the catalytic reaction followed pseudo first-order and the average values of the first-order rate constant for CuFe2O4, MnFe2O4, CoFe2O4 and NiFe2O4 were observed to be 0.0031 s−1, 0.0013 s−1, 0.0011 s−1 and 0.0007 s−1, respectively. These results confirm the catalytic activities of metal ferrite MNPs in the order of CuFe2O4 > MnFe2O4> CoFe2O4 > NiFe2O4.