Catalytic studies of NiFe2O4 nanoparticles prepared by conventional and microwave combustion method

Abstract

A simple and rapid synthesis has been developed to synthesize NiFe2O4 nanoparticles with tunable optical, magnetic and catalytic properties by using Hibiscus rosa sinensis plant extract in the current study. The crystalline structure of the synthesized NiFe2O4 nanoparticles was confirmed by X-Ray diffraction (XRD) and Rietveld refinement analysis. Morphological, elemental, magnetic and optical properties of the synthesized nanoparticles were interpreted by fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), UV–Visible diffused reflectance spectroscopy (UV-DRS), photoluminescence (PL) studies, and vibrating sample magnetometer (VSM). XRD analysis showed the single phase crystalline nature with average crystallite size of 50–70 nm. SEM and EDX analysis recognize the spherical shape nanoparticles and phase purity of the samples. The optical band gap is determined using UV-DRS spectra and is observed to decrease with increasing the calcination temperature. VSM studies obviously demonstrate the ferromagnetic property of the samples. The value of saturation magnetization has decreased with an increase in the calcination temperature and the coercivity is decreased. Additionally, NiFe2O4 nanoparticles were investigated for the catalytic reduction capability for different dyes like Rhodamine-B (Rh-B), Methylene blue (MB), Rose Bengal (RB), and Congo red (CR). It is found that the dye solution was degraded with increasing irradiation time. Hence, the prepared nanoparticles have been used as high potential catalysts for the reduction of organic dyes in the application of waste water treatment. NiFe2O4 is an active agent in catalyzing the oxidation of glycerol to formic acid with good conversion percentage and high selectivity. This catalytic system in the polar solvents, such as, acetonitrile provides the enhanced conversion results. The very important role played by a variety of reaction parameters in deciding the catalytic effectiveness is well established and every parameter has an optimal value to acquire the maximum catalytic activity.