Magnetic recoverable Cu/CuFe2O4 nanocomposite as an efficient catalyst for 4-nitrophenol reduction and methylene blue degradation

Abstract

In this study, the magnetic Cu/CuFe2O4 nanocomposite was successfully prepared by a one-pot solvothermal method and evaluated for catalytic activity in the 4-nitrophenol (4-NP) reduction reaction and methylene blue (MB) degradation reaction. The structure, surface morphology, and properties of this catalyst were characterized by using several physicochemical methods such as Powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET), field emission scanning electron microscopy (FE-SEM), EDX mapping, and vibrating sample magnetometer (VSM). The Cu/CuFe2O4 catalyst is spherical in shape with an average diameter of about 145 nm and a BET surface area (SBET) of 52 m2.g-1. In both the 4-NP reduction and MB degradation reactions, this nanocomposite material showed high catalytic activity. The yield of 4-NP reduction reaction in the presence of NaBH4 was 82% after 5 minutes. In this reaction, Cu metal both plays the role of direct electron transfer from BH4- ions to 4-NP and participates in and promotes the electron transfer process between Cu+-Cu2+ and Fe2+-Fe3+ ion pairs in CuFe2O4. For MB degradation reaction, under the stimulation of UVA radiation with the presence of oxalic acid (H2C2O4) as a free radical-generating agent, the reaction yield was 98% after 40 minutes. In this process, Cu is an electron donor to reduce Fe3+ to Fe2+ in the CuFe2O4 structure, contributing to promoting the formation of highly active free radicals to decompose MB. The catalytic efficiency, crystal structure, and morphology of Cu/CuFe2O4 nanocomposite were stable over five consecutive uses in both two reactions.