Preparation of magnetic Ag/CoFe2O4 composite as an antibacterial material and efficient catalyst for 4-nitrophenol reduction

Abstract

In this study, CoFe2O4 (CFO) material was prepared by hydrothermal method and then used to synthesize nanometer-sized magnetic Ag/CoFe2O4 (Ag/CFO) composite. Ag/CFO materials were also prepared by the hydrothermal technique of AgNO3 solution containing CFO and investigated as a catalyst to reduce 4-nitrophenol (4-NP). The structure, surface morphology and properties of the materials were analyzed by physicochemical methods, including X-ray diffraction (PXRD), Fourier - transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscopy (FE-SEM), EDX mapping, and vibrating sample magnetometer (VSM). Ag/CFO composite materials are granular with an average diameter of about 18 - 20 nm. Although the Ag content in Ag/CFO is small (0.34% atom), the material has a high catalytic activity in 4-NP reduction in the presence of NaBH4, with a reaction efficiency greater than 99% only in one minute reaction time. In this reaction, the Ag component in Ag/CFO acts as a direct electron transfer from the BH4- ion to 4-NP, to form 4-aminophenol (4-AP). In addition, Ag/CFO also showed good antibacterial effect against both the Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacterium Pseudomonas aeruginosa.