Synthesis of Active MFe2O4/γ-Fe2O3 Nanocomposites (Metal = Ni or Co) for Reduction of Nitro-Containing Pollutants and Methyl Orange Degradation

Abstract

Metal-ferrite/maghemite nanocomposites (NiFe2O4/***[Formula: see text]-Fe2O3 and CoFe2O4/[Formula: see text]-Fe2O[Formula: see text] were synthesized via doping maghemite with metal salt (NiCl2 or CoCl[Formula: see text] followed by reduction of metal ions using NaBH4. The synthesized metal-ferrite/maghemite nanocomposites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR) and the amounts of the dopant-metal (Ni/Co) were determined using ICP-OES technique. Results showed that this synthetic route produced nanocomposites with highly active ferrite phases MFe2O4. The synthesized nanocomposites exhibited exceptional catalytic activities for the reduction of 4-nitrophenol and 2-nitroaniline as well as the catalytic degradation of methyl orange. Specific activity parameter of NiFe2O4/[Formula: see text]-Fe2O3 and CoFe2O4/[Formula: see text]-Fe2O3 toward reduction of 4-NP reached 993.9 and 929.8[Formula: see text]s[Formula: see text][Formula: see text]g[Formula: see text], respectively. These high values of specific activities are higher than most reported metal-ferrite composites prepared via traditional co-precipitation methods. Besides, strong magnetic properties of the prepared metal-ferrite/maghemites facilitates easy separation process for several reuses.