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Synthesis and magnetic properties of octahedral ferrite NiχCo1−χ Fe2O4 nanocrystals

100%

Kasapoglu N., Birsöz B., Baykal A., Köseoglu Y., Toprak M.

Open Chemistry

2007

vol. 5

issue 2

570-580

A series of Ni doped cobalt ferrite compounds with the formula Niχ Co1−χ Fe2O4 where x=0, 0.2, 0.4, 0.6, 0.8, and 1.0 were prepared using a hydrothermal method and subsequently sintered/annealed at 600 °C for 3 h. The influence of the Ni content on the lattice parameter, a, stretching vibration and the magnetization of specimens were subsequently studied. XRD and FTIR were used to investigate structure and composition variations. All samples were found to have a cubic spinel structure. SEM was used to study morphological variations. The results indicate that the average particle sizes are between 30–35 nm with a narrow size distribution along with nanocrystals forming of regular octahedrons. A decrease in the peak to peak line width and increase in resonance field with increasing Ni content were observed from ESR measurements. Based on ESR results, a core-shell type of formation was proposed where the core is made up of undoped CoFe2O4 and the shell is Ni2+ doped CoFe2O4. [...]

Synthesis, characterization and magnetic investigation of (NH4)0.5Mn1.25(H2O)2[BP2O8]·0.5H2O

88%

Birsöz B., Baykal A., Toprak M., Köseoglu Y.

Open Chemistry

2007

vol. 5

issue 2

536-545

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. [...]

Renewable chitin from marine sponge as a thermostable biological template for hydrothermal synthesis of hematite nanospheres using principles of extreme biomimetics

75%

Wysokowski M., Petrenko I., Motylenko M., Langer E., Bazhenov V. V., Galli R., Stelling A. L., Kljajić Z., Szatkowski T., Kutsova V. Z., Stawski D., Jesionowski T.

Bioinspired Materials

2014

vol. 1

issue 1

Chitin originating from marine sponges possesses a unique nanofibrillar network structure that is the basic element of the microtubular scaffold-like skeleton of these organisms. Sponge chitin represents an intriguing example of thermostability, as it is stable up to 400 °C. It also constitutes a renewable biological source due to the high regeneration ability of Aplysina sponges under marine farming conditions. These properties can be exploited for the facile and environmentally friendly creation of novel, biocompatible organic-inorganic hybrid materials with a range of uses. Here, chitin-based scaffolds isolated from the skeleton of marine demosponge Aplysina aerophoba were used as a template for the in vitro formation of iron oxide from a saturated iron(III) chloride solution, under hydrothermal conditions (pH~1.5, 90 °C). The resultant chitin-Fe2O3 three dimensional composites, prepared for the first time via hydrothermal synthesis route, were thoroughly characterized using light, fluorescence and scanning electron microscopy; as well as with analytical methods like Raman spectroscopy, electron diffraction and HR-TEM. The results show that this versatile method allows for efficient chitin mineralization with respect to hematite. Additionally, we demonstrate that chitin nanofibers template the nucleation of uniform Fe2O3 nanocrystals.

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2 Open Chemistry

1 Bioinspired Materials

1 2015

2 2007

2 Baykal A.

2 Birsöz B.

2 Köseoglu Y.

2 Toprak M.

1 Bazhenov V. V.

1 Galli R.

1 Jesionowski T.

1 Kasapoglu N.

1 Kljajić Z.

1 Kutsova V. Z.

1 Langer E.

1 Motylenko M.

1 Petrenko I.

1 Stawski D.

1 Stelling A. L.

1 Szatkowski T.

1 Wysokowski M.

Search results

Synthesis and magnetic properties of octahedral ferrite NiχCo1−χ Fe2O4 nanocrystals

Synthesis, characterization and magnetic investigation of (NH4)0.5Mn1.25(H2O)2[BP2O8]·0.5H2O

Renewable chitin from marine sponge as a thermostable biological template for hydrothermal synthesis of hematite nanospheres using principles of extreme biomimetics