Enhancing the catalytic activity of recyclable nanocrystalline NiFe2O4 by replacing Ni by Cu

Abstract

Herein, we report an efficient, magnetically recoverable and recyclable nanocatalyst to drive a reduction reaction under mild reaction conditions. Nickel ferrite (NiFe 2 O 4) and 20% copper substituted nickel ferrite (Ni 0.8 Cu 0.2 Fe 2 O 4) nanocatalysts were synthesized using a facile glycine-nitrate autocombustion route and employed as catalysts to assess the reduction of 4-nitrophenol in aqueous medium. Phase purity, structural aspects, morphological features and magnetic characteristrics of as-synthesized ferrite powders were carried out using Xray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). Elemental compositions of the prepared materials were investigated using EDX analysis. Reduction of 4nitrophenol to 4-aminophenol using NaBH 4 as the reducing agent with the nanocatalyst was monitered using a UV-Visible spectrophotometry. The results indicate that the Ni 0.8 Cu 0.2 Fe 2 O 4 demonstrated a better catalytic activity with nearly 99% conversion against NiFe 2 O 4 , which showed almost negligible activity over a long period of time. For the first catalytic reduction cycle, time taken by the Ni 0.8 Cu 0.2 Fe 2 O 4 was less than 2 min. However, the reduction time increased progressively as number of cycles increased. Ni 0.8 Cu 0.2 Fe 2 O 4 also displayed a superior catalytic performance over 10 cycles, without a significant drop in its activity. The superior catalytic performance of Ni 0.8 Cu 0.2 Fe 2 O 4 is likely to be due the surface contribution of smaller particles and the presence of Cu 2+ at the octahedral site of the spinel ferrite.

Tunable Dielectric Properties of Nickel Ferrite Derived via Crystallographic Site Preferential Cation Substitution

“…Nickel ferrite (NiFe 2 O 4 ; NFO) is one of the metal-oxide-based soft magnetic materials owing to its high magnetization at low magnetic fields and low coercive force. , The physical, chemical, and electromagnetic properties of NFO and NFO-based composites are attractive for utilization in numerous scientific and technological applications. − Due to the intrinsic nature of NFO, it has been employed as a suitable active material in a wide range of applications, which include electronic memory, biomedical sensors and actuators, telecommunication, electromagnetic interference (EMI) shielding, catalysis, energy storage, and high-frequency electromagnetic devices. − The recent attention to the intrinsic and doped NFO materials is primarily due to the possibility of the design and development of their nanoscale architectures for utilization in electromagnetics, electrochemical energy storage and conversion technologies, and biomedical applications. − Additionally, using intrinsic or doped NFO in multilayered structures or in conjunction with polymers has been proposed to design highly efficient EMI shielding materials . For instance, the EMI absorber materials designed by means of a multilayer assembly of poly­(vinylidene fluoride)-containing Zn-doped NFO have shown to increase the EMI shielding effectiveness dramatically .…”

“…Therefore, understanding the electrical, magnetic, and dielectric properties of intrinsic and doped NFO nanomaterials warrants further investigations. Furthermore, compared to bulk materials, transition-metal-based engineered nanostructured materials are expected to provide excellent opportunities to tailor and/or manipulate the quantum effects and thereby derive novel electrical, optical, and magnetic properties. − …”

A facile chemical synthesis of CuxNi(1−x)Fe2O4 nanoparticles as a nonprecious ferrite material for electrocatalytic oxidation of acetaldehyde

“…The expansion of the crystal volume of the designed CuNFNPs can be attributed to the doping of Cu 2+ which has slightly larger radii than Ni 2+ . The radii of Cu 2+ and Ni 2+ are 0.57 and 0.55 Å, respectively 27 . Therefore, the replacement of Ni 2+ by larger size metallic ion (Cu 2+ ) can increase the crystal parameters and volume as found in the designed CuNFNPs 28,29 .…”

ONE POT POLYOL SYNTHESIS OF Fe2O3-Fe3O4 NANO COMPOSITES AND THEIR STRUCTURAL, OPTICAL, PROPERTY STUDIES

“…Over the last few years magnetic materials have been studied for photo-catalysis and water splitting application. Magnetic nanoparticles as photo catalysis have the advantage over non-magnetic photo-catalysts that they can be recovered by magnetic separation and can be reused multiple times [7][8][9][10]. Ferrites such as ferric oxide and ferrous oxide are interesting materials for photo catalysis and hydrogen production application.…”

“…Ferrites chemically stable, nontoxic and large quantities could be processed cost effectively. Cation distribution, surface area and morphology of ferrites play significant role in performance as catalyst [8,11]. Kaneko et al prepared multicomponent zinc ferrites and studied their ability for hydrogen production in presence of sun light by water splitting.…”