Flower-like Bi2O2CO3/NiFe2O4 magnetically recoverable nanocomposites: Preparation, characterization and their catalytic application in the reduction of 4-nitrophenol to 4-aminophenol

Abstract

In this work, a series of novel flower–like Bi2O2CO3/NiFe2O4 nanocomposites (denoted as BOC/NFO) with different amounts of NiFe2O4 (NFO) content was successfully synthesized for the first time by a simple and feasible hydrothermal method. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), vibrating sample magnetometer (VSM), and N2 adsorption–desorption analysis were utilized to analyze the structure, morphology, size, phase composition, optical and magnetic properties of the synthesized nanocomposites. The results demonstrated the successful deposition of uniform NFO nanoparticles onto the surface of flower–like BOC nanostructures. Then, the catalytic activity of magnetic BOC/NFO nanocamposites was investigated for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by using sodium borohydride (NaBH4) in aqueous solution and at room temperature. The results showed that BOC/NFO15 nanocamposite with 15 %wt. NFO exhibited the best performance in the reduction of 4-NP with 100% conversion into the corresponding amino derivative within 26 min with rate constant equal 0.14 min−1. The effect of catalyst dosage was also investigated on the efficiency of reduction process. It was found that the present catalyst could also catalyze the complete reduction of 2-nitrophenol (2-NP) and 4-nitroaniline (4-NA) and 2-nitroaniline (2-NA) to corresponding amines within short reaction times of 14–27 min. In addition, deposition of magnetic NFO nanoparticles onto the surface of the BOC nanoflowers proved to be an effective way to separate catalyst easily from the reaction system with an external magnetic field, allowing them to be reused in multiple cycles without any change in structure.