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► The synthesized PPCA coated Fe3O4 NPs might be applied magnetic heterogeneous catalyst. ► Superparamagnetic Fe3O4–PPCA NPs were fabricated by reflux route for the first time in this ...study. ► The product has potential applications in nanoelectronics and biomedical devices.
Piperidine-4-carboxylic acid (PPCA) functionalized Fe3O4 nanoparticles as a novel organic–inorganic hybrid was fabricated and characterized by XRD, FT-IR, VSM, and TEM techniques. Its detailed electrical properties are also presented. Composition was determined as Fe3O4, while particles were observed to have spherical morphology. VSM measurement proved the super-paramagnetic property of the as synthesized nanocomposite. ac and dc conductivity measurements indicated semiconductor characteristics and changing trends with temperature because of reorganization of the nanocomposite. dc conductivity is strongly temperature dependent and is classified into three regions. Analysis of the real and imaginary parts of the permittivity of nanocomposite showed the ionic polarization mechanism consisting of ionic conductivity and interfacial polarization.
In this study, the effect of temperature on the hydrothermal synthesis of single-phase SrFe sub(12)O sub(19) hexaferrite (SrM) was investigated. For this synthesis, annealing or calcination process ...was applied. The Fe/Ba molar ratio was taken as 8:1. In this study, single-phase SrM NPs were synthesized via hydrothermal method. XRD patterns showed the presence of the hard (SrM) phase in the samples treated at 200 and 220 super(compfn)C. Besides, formation of hexagonal plate-like samples was observed in SEM micrographs. Despite the low magnetization and coercive field values, the presence of the SrM phase was also shown in magnetization measurements. A reduced magnetization was explained by the existence of SrCO sub(3) and Fe sub(2)O sub(3) phases, and a high shape anisotropy is probably the reason of low coercivity.
Magnetically recovable BaFe
12
O
19
–APTES–Pd(0) and SrFe
12
O
19
–APTES–Pd(0) catalysts were easily synthesized by immobilizing Pd nanoparticles on the surface of magnetic hexaferrite–NH
2
...microspheres. It was found that the combination of BaFe
12
O
19
, SrFe
12
O
19
and 3-aminopropyltriethoxysilane (APTES) could give rise to structurally stable catalytic sites. Furthermore, BaFe
12
O
19
–APTES–Pd(0) and SrFe
12
O
19
–APTES–Pd(0) magnetically recyclable nano catalysts (MRCs) can be recovered by magnet and reused for nine runs for hydrogenation of 4-nitroaniline and dinitribenzene without significant loss in its catalytic activity which shows the indicative of a potential applications of these catalyst in industry.
Polyaniline (PANI)/cobalt-manganese ferrite, PANI/Co
0.5
Mn
0.5
Fe
2
O
4
, nanocomposite was synthesized by oxidative chemical polymerization of aniline in the presence of ammonium peroxydisulfate. ...Microwave assisted synthesis method was used for the fabrication of core Co
0.5
Mn
0.5
Fe
2
O
4
nanoparticles. The presence of PANI on the surface of the Co
0.5
Mn
0.5
Fe
2
O
4
NPs was confirmed by infrared spectroscopy and thermal gravimetric analysis. The crystallite size was calculated with line profile fitting method as 20 ± 9 nm. The spherical morphology of the product was presented by Scanning electron microscopy and transmission electron microscopy. The electrical characterizations showed that ac conductivity is found to be independent of frequency and increases with increase of temperatures. However, imaginary component of dielectric function obey the power law of frequency while it is almost independent of temperature. This can be attributed to the molecular interatomic interaction between Co
0.5
Mn
0.5
Fe
2
O
4
nanoballs and PANI shells.
Co1-xZnxFe2O4 spinel nanoparticles with Zn concentrations of x = 0.0, 0.2 were prepared by a hydrothermal route in the presence of triethylene glycol (TEG). The structural, magnetic, electrical and ...dielectric properties of the prepared nanoparticles were studied. The XRD results confirmed the formation of single spinel ferrite structure with crystallite size 9 and 10 nm for x = 0.0 and 0.2 compositions respectively. The lattice parameter (a) increased with increasing Zn concentration. Temperature and frequency dependent electrical and dielectric properties of the prepared ferrites have also been investigated. Our findings show that overall conductivity of Co0.8Zn0.2Fe 2O4 nanoparticle is lower than that of CoFe 2O4 and roughly in the range of 10-11-10 -7 S cm-1 depending strongly temperature and frequency owing to the formation of stable electric bonds between the Zn2+ and Fe2+ ions, which localizes Fe2+ charge carriers. The ac conductivity showed a temperature dependent behavior at low frequencies and temperature independent behavior at high frequencies, which is an indication of ionic conductivity. dc conductivity of Co0.8Zn0.2Fe 2O4 nanoparticle are found to obey the Arrhenius plot and can be classified into two regions over with activation energy of 0.113 and 0.163 eV in the ranges of 20-40 °C and 70-120 °C, respectively when CoFe2O4 has an activation energy of 0.245 eV.
A new borophosphate compound with the composition (NH4)χ Mn((3−χ)/2)(H2O)2 BP2O8·(1−x)H2O was prepared under mild hydrothermal conditions and characterized by X-ray powder diffraction (XRD) and ...Fourier Transform Infrared Spectroscopy (FTIR) methods. The title compound was synthesized from MnCl2·2H2O, H3BO3, and (NH4)2HPO4 with variable molar ratios by heating at 180 °C for 7 days in an autoclave. The X-ray diffraction data of the water insoluble polycrystalline powder was indexed using the TREOR program in hexagonal system with the unit cell parameters of a = 9.5104, c = 15.7108 Å, Z = 6 and the space group P65 (No.176). (NH4)χ Mn((3−χ)/2)(H2O)2 BP2O8·(1−x)H2O is isostructural with (NH4)χ M ((3−χ)2)/II (H2O)2 BP2O8·(1−x)H2O (MII = Co, Cd, Mg; x = 0.5–1). Its unit cell parameters and hkl values were in good agreement with the other isostructural compounds. This is the first report presenting both the synthetic details and the indexed X-ray powder diffraction pattern of this compound along with the characterization by FTIR, thermal gravimetric analysis, scanning electron microscopy and EPR.
The 1,3-bis(2-benzimidazyl)-2-thiapropane (TP^sub 2^) and 1,5-bis(2-benzimidazyl)-3-thiapentane (TP^sub 3^) ligands form 5-coordinate square pyramidal monometallic complexes with PdCl^sub 2^. In both ...complexes the ligands act as chelating tridentate, through two of the nitrogen atoms in the imidazole ring and the sulphur atom of the bridging group. The ligands and complexes were characterised by analytical data and by modern spectroscopic methods such as FT-Raman, i.r., ^sup 1^H and ^sup 13^C-n.m.r. spectra.PUBLICATION ABSTRACT
Nanoparticles (NPs) of CoFe sub(2)O sub(4), which is a well-known spinel ferrite and hard magnetic material with very high cubic magnetocrystalline anisotropy, were synthesized by co-precipitation ...method. The effect of different molecular weights of polyethyleneglycol (PEG) on the magnetic properties and crystallite size of CoFe sub(2)O sub(4) NPs was investigated by using PEG-400, PEG-10.000 and, PEG-20.000. Crystalline structure and size of CoFe sub(2)O sub(4) NPs were studied using X-ray diffraction (XRD). The VSM studies showed that the saturation magnetization (M sub(s )) and coercivity (H sub(c )) of the CoFe sub(2)O sub(4) NPs depend on molecular weight of PEG.
Polyaniline-MnFe sub(2)O sub(4)-CTAB nanocomposite was successfully synthesized by using 1-butyl-3-methyl-imidazolium trifluoromethane sulfonate (RTILs) as ionic liquid and Cetyl trimethylammonium ...bromide (CTAB) as surfactant via in-situ polymerization. The calculated average crystallite size, D sub(XRD), of the product was 26 plus or minus 4 nm. Conductivity and permittivity properties of Polyaniline-MnFe sub(2)O sub(4) nanocomposite was also exemplified by means of an impedance spectroscopy, which would be evaluated at frequency ranges up to 3 MHz for temperature range of 20-120 degree C. In general, ac conductivity remains almost unchanged until it reaches up to 160 kHz, and then reduces slightly almost for all temperatures except for some slight fluctuation somehow at lower temperatures. The values fluctuate between 1.1-1.6 mS/cm at above all temperatures.
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