Structural, Magnetic, and Catalytic Evaluation of Spinel Co, Ni, and Co–Ni Ferrite Nanoparticles Fabricated by Low-Temperature Solution Combustion Process

Abstract

Here, we present the low-temperature (∼600 °C) solution combustion method for the fabrication of CoFe 2 O 4 , NiFe 2 O 4 , and Co 0.5 Ni 0.5 Fe 2 O 4 nanoparticles (NPs) of 12–64 nm range in pure cubic spinel structure, by adjusting the oxidant (nitrate ions)/reductant (glycine) ratio in the reaction mixture. Although nitrate ions/glycine (N/G) ratios of 3 and 6 were used for the synthesis, phase-pure NPs could be obtained only for the N/G ratio of 6. For the N/G ratio 3, certain amount of Ni 2+ cations was reduced to metallic nickel. The NH 3 gas generated during the thermal decomposition of the amino acid (glycine, H 2 NCH 2 COOH) induced the reduction reaction. X-ray diffraction (XRD), Raman spectroscopy, vibrating sample magnetometry, and X-ray photoelectron spectroscopy techniques were utilized to characterize the synthesized materials. XRD analyses of the samples indicate that the Co 0.5 Ni 0.5 Fe 2 O 4 NPs have lattice parameter larger than that of NiFe 2 O 4 , but smaller than that of CoFe 2 O 4 NPs. Although the saturation magnetization ( M s ) of Co 0.5 Ni 0.5 Fe 2 O 4 NPs lies in between the saturation magnetization values of CoFe 2 O 4 and NiFe 2 O 4 NPs, high coercivity ( H c , 875 Oe) of the NPs indicate their hard ferromagnetic behavior. Catalytic behavior of the fabricated spinel NPs revealed that the samples containing metallic Ni are active catalysts for the degradation of 4-nitrophenol in aqueous medium.

Borohydride-Assisted Surface Activation of Co3O4/CoFe2O4 Composite and Its Catalytic Activity for 4-Nitrophenol Reduction

“…15 These byproducts might also be catalytically active in the reduction of 4-NP. In particular, the purity and size of the cobalt ferrite particles obtained using a solution combustion process depend on several factors such as: (i) oxidizing and reducing agent ratio, 16 (ii) annealing temperature, and (iii) annealing time. Apart from α-Fe 2 O 3 , CoO, and Co 3 O 4 , the generated byproducts can also contain the clusters or particles of cobalt, iron oxohydroxydes (e.g., FeOOH), amorphous materials, etc., 10,12 the catalytic behaviors of which are unknown.…”

An integrated photoanode based on non-critical raw materials for robust solar water splitting

“…Finally, the Raman spectrum corresponding to the region (iii), which is related to the interface between the Fe-rich aggregates and the nickel oxide on the substrate surface, shows the phonon modes at 200 cm À1 (F 2g ), 290 cm À1 (E g ) and 460 cm À1 (F 2g ), characteristic of oxygen atom bending in M-O bond at octahedral voids of the spinel NiFe 2 O 4 , and the band at 675 cm À1 (A 1g ), related to a stretching mode of the oxygen atom concerning metal-ion binding in the tetrahedral void, confirming the formation of the mixed oxide NiFe 2 O 4 . 55,56 The Raman spectrum of the Ni foil sample after the thermal treatment taken as the reference is provided in ESI, † Fig. SI6, showing a principal signal around 536 cm À1 , characteristic of the Ni-O stretching mode of the NiO phase.…”

Magnetic Nanomaterials for Magnetically-Aided Drug Delivery and Hyperthermia

“…The main obstacle of this procedure is the control of nanoparticle size and polydispersity. One of the major advantages is the opportunity to synthesize composite materials [72][73][74][75]. While normal micelles form in an aqueous medium, reverse micelles form in hydrophobic media [68,70].…”