Ferrite nanoparticles (FNPs) have attracted a great interest due to their wide applications in several areas such as biomedical, wastewater treatment, catalyst and electronic device. This review focuses on the synthesis, characterisation and application of FNPs in electronic device with more emphasis on the recently published works. The most commonly used synthesis techniques along with their advantages and limitations are discussed. The available characterisation techniques and their application in electronic materials such as sensors and biosensors, energy storage, microwave device, electromagnetic interference shielding and high-density recording media are briefly reviewed.

Ferrite nanoparticles: Synthesis, characterisation and applications in electronic device

Application of spinel ferrite nanoparticles in water and wastewater treatment: A review

Transition metal oxides – Thermoelectric properties

A highly efficient and environmentally-friendly oxidation process is always desirable for air purification. This study reported a novel carbon quantum dots (CQDs)/ZnFe2O4 composite photocatalyst for the first time through a facile hydrothermal process. The CQDs/ZnFe2O4 (15 vol %) composite demonstrates stronger transient photocurrent response, approximately 8 times higher than that of ZnFe2O4, indicating superior transfer efficiency of photogenerated electrons and separation efficiency of photogenerated electron–hole pairs. Compared with pristine ZnFe2O4 nanoparticles, CQDs/ZnFe2O4 displayed enhanced photocatalytic activities on gaseous NOx removal and high selectivity for nitrate formation under visible light (λ > 420 nm) irradiation. Electron spin resonance analysis and a series of radical-trapping experiments showed that the reactive species contributing to NO elimination were ·O2– and ·OH radicals. The possible mechanisms were proposed regarding how CQDs improve the photocatalytic performance of ZnFe2...

Environment-Friendly Carbon Quantum Dots/ZnFe2O4 Photocatalysts: Characterization, Biocompatibility, and Mechanisms for NO Removal.

Photocatalytic application of spinel ferrite nanoparticles and nanocomposites in wastewater treatment: Review

Highly stable and magnetically recoverable MFe 2 O 4 (M = Zn, Co, Mn) spinel ferrite nanoparticles; synthesized using sol gel-hydrothermal technology via utilizing polyvinyl alcohol surfactant, were proposed as heterogeneous catalysts for the reduction of nitroarenes. The morphological characteristics, structural exploration, surface, optical, vibrational and magnetic properties were performed using powder X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive X-ray, N 2 sorptiometry, diffused UV–vis reflectance spectroscopy, FTIR, point of zero charge, vibrating sample magnetometer (VSM) and thermokinetic analysis via TGA technique. The results showed that MnFe 2 O 4 exhibited the best performance in the reduction of 4-nitrophenol (4-NP), 2,4,6 tri-nitrophenol (2,4,6-NP) and 4-nitroaniline (4-NA) and revealed 100% conversion into the corresponding amino derivatives in 270 sec with rate constant equal 0.01061 s −1 , 0.01134 s −1 and 0.01355 s −1 , respectively. The superiority of the catalytic reduction of MnFe 2 O 4 was due to increasing the pore radius and pore volume (6.75 nm, 0.227 cm 3 /g) values compared to other nanoferrites. The synthesized nanoferrites indicate independence of the activity on crystallite sizes due to the insignificant margin of change (from 6 to10 nm). Conversely, decreasing the activity of ZnFe 2 O 4 was due to increasing the Zn 2+ ions size that induces an increase in lattice parameter values and thus increases the long-range electron transfer between Fe 2+ –Fe 3+ ions. The MnFe 2 O 4 catalyst that presented the highest saturation magnetization (135 emu/g) indicated the highest reduction potential for 4-NA comparatively in the presence of NaBH 4 and the reduction reaction followed pseudo first-order kinetics. Increasing the reduction performance of 4-NA compared to other nitroaromatics on MnFe 2 O 4 was explained based on the formed intermediates, their reactivities, hydrophobicity and to point of zero charges. It has been explored that the reduction efficacy of 4-NP was enhanced on MnFe 2 O 4 with the addition of ammonium oxalate and benzoquinone where it was inferior following the addition of tertiary-butyl alcohol. More important correlations concerning the effect of octahedral sites, residual organics, heat of activation ( E a ) and activation free energy (Δ G *) values; determined while the removal of citrate/PVA moieties, on nitroarenes reduction rates were well scrutinized and discussed.

Synthesis of magnetically recyclable spinel ferrite (MFe2O4, M = Zn, Co, Mn) nanocrystals engineered by sol gel-hydrothermal technology: High catalytic performances for nitroarenes reduction

Electrical and optical properties of highly oriented nanocrystalline vanadium pentoxide

The aqueous polymerization of 3-hydroxyaniline (3HA) was studied using sodium dichromate as oxidant in presence of hydrochloric acid. The effect of hydrochloric acid, sodium dichromate and monomer concentration on the polymerization rate, specific viscosity of the obtained polymer and a.c.conductivity was investigated. The initial and overall reaction rates increase with the increase in hydrochloric acid concentration or sodium dichromate concentration but decrease with the increase in the monomer concentration. The specific viscosity values increase with increasing of hydrochloric acid concentration or monomer concentration which means that the molecular weight of the polymer samples increases in the same direction. But the molecular weight decreases with increasing sodium dichromate concentration. The highest a.c. conductivity value of the obtained polymer was found in case of using 0.0019 g mol/L of Na 2 Cr 2 O 7 , 0.1 M HCl and 0.1 M monomer solution in the reaction medium. Some electrical properties ...

Kinetic studies of the aqueous oxidative polymerization of 3-hydroxyaniline and characterization of the polymer obtained

Mossbauer and IR spectra as well as the electrical conductivity have been measured to give an idea about the structure and the electrical properties of some rare earth tellurite glasses containing Fe2O3. The glasses denoted [1 − (2x + 0.05)] TeO2 ·xFe2O3 · (x + 0.05) Ln2O3, wherex = 0.0 and 0.05 and Ln = lanthanum, neodymium, samarium, europium or gadolinium, were prepared by fusing a mixture of their respective reagent grade oxides in a platinum crucible at 800° C for one hour. The Mossbauer parameters such as isomer shift, quadruple splitting and line width were found to be a function of the polarizing power (charge/radius) of the rare earth cations. The Mossbauer parameters were not affected by the heat treatment of the glass samples. Both of the Te-O-Ln and Te-O-Fe stretching vibrations were obtained from the IR results which indicate that the rare earth oxides and iron oxide are partially covalent. The electrical resistivity was measured as a function of temperature from 293 to 520 K. Both the electrical resistivity and the activation energy were found to be a function of the atomic number (Z) of the rare earth cations. The results were interpreted on the basis of the electronic structure of the glass.

A. A. Bahgat

Papers

Synthesis of magnetically recyclable spinel ferrite (MFe2O4, M = Zn, Co, Mn) nanocrystals engineered by sol gel-hydrothermal technology: High catalytic performances for nitroarenes reduction

Electrical and optical properties of highly oriented nanocrystalline vanadium pentoxide

Kinetic studies of the aqueous oxidative polymerization of 3-hydroxyaniline and characterization of the polymer obtained

Physical properties of some rare earth tellurite glasses

Optical and electrical properties of binary WO3-Pb3O4 glasses