the aim of this research is to study ni2+ supported on hydroxyapatite-core-shell magnetic γ-fe2o3 nanoparticles (γ-fe2o3@hap-ni2+) as a green and recyclable catalyst for the biginelli reaction under solvent-free conditions. one-pot multi-component condensation of 1,3-dicarbonyl compounds, urea and aldehydes at 80 oc affords the corresponding compounds in high yields and in short reaction times ...

The phase control, hierarchical architecturing and hybridization of iron oxide is important for achieving multifunctional capability for many practical applications. Herein, hierarchically structured reduced graphene oxide (hrGO)/α-Fe2O3 and γ-Fe3O4 nanobox hybrids (hrGO/α-Fe and hrGO/γ-Fe NBhs) are synthesized via a one-pot, hydrothermal process and their functionality controlled by the crysta...

The process of reductive dissolution of α-Fe2O3, Ba-hexaferrite, α-FeOOH, γ-Fe2O3, γ-FeOOH, and ferrihydrite can be monitored continuously by abrasive stripping voltammetry and chronoamperometry to obtain information about homogeneity of reactivity and about the particle size of the pure phases and mixtures. Phase parameters (rate constant and charge transfer coefficient) and the geometrical fa...

We have investigated the role of the grain boundary on the resistive magnetodielectric property of polycrystalline γ -Fe2O3 through impedance spectroscopy measurements. Depending on the sample preparation temperature, the dielectric constant of γ -Fe2O3 is significantly different especially at low frequencies (<104 Hz) and high temperatures (>200 K). The value of the magnetodielectric effect at...

Although individual γ-Fe2O3 and α-Fe2O3 have been widely fabricated for gas sensors, their mixed phase of α/γ-Fe2O3 might deliver excellent sensing properties. In this study, a facile solvothermal method was used to fabricate Fe-alkoxide. After thermal treatment, it converted into γ-Fe2O3, mixed-phase with nanosheets-assembled flower-like structure. We studied the influence calcination temperat...

Synthesis of core–shell nanostructures with magnetic core and zeolitic shell is an ongoing challenge. Herein, a strategy presented for preparation γ-Fe2O3@mesoporous silica (mSiO2) nanoparticles containing ultrasmall domains silicalite-1 in the (γ-Fe2O3@mSiO2/silicalite-1). The consists solid-state reorganization precursor amorphous mSiO2 into using tetrapropylammonium hydroxide (TPAOH) as orga...

We present a different strategy for synthesizing the Au-γ-Fe2O3 bifunctional nanoparticle by using a larger (50 nm) Au nanoparticle as the core surrounded by smaller (10 nm) γ-Fe2O3 nanoparticles. The synthesis of the composite nanoparticles is quite facile based on a simple redox process whereby Fe2+ is used to reduce Au3+. The morphology and composition of the product is measured by transmiss...

The aim of this research is to study Ni2+ supported on hydroxyapatite-core-shell magnetic γ-Fe2O3 nanoparticles (γ-Fe2O3@HAp-Ni2+) as a green and recyclable catalyst for the Biginelli reaction under solvent-free conditions. One-pot multi-component condensation of 1,3-dicarbonyl compounds, urea and aldehydes at 80 oC affords the corresponding compounds in high yields and in short reaction times ...

BACKGROUND During liquid-phase synthesis of γ-Fe2O3 nanoparticles by chemically induced transition in FeCl2 solution, enhancement of surface modification by adding ZnCl2 was attempted by using NaOH. By using transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectrometry, and vibrating sample magnetometry, the dependence of the synthes...

The field-induced assembly of γ-Fe2O3 nanoparticles under alternating magnetic field of different frequency was investigated. It was found that the assembly was dependent upon the difference between colloidal relaxation time and field period. The same experiments on DMSA-coated γ-Fe2O3 nanoparticles exhibited that the relaxation time may be mainly determined by the magnetic size rather than the...