We report a new optical sensing approach based on the chiral recognition of optically active CoFe2O4magnetic nanoparticles by CdSe/CdS core/shell quantum dots stabilized with cysteine of different chiralities.
In this paper, we report a new modified solution combustion synthesis technique for one-step production of metallic Co nanoparticles. The main unique feature of our approach is the use of microwave-assisted foam preparation. Also, the effect of different types of fuels (urea, citric acid, glycine, and hexamethylenetetramine) on the combustion process and characteristics of resultant solid products were investigated. It was shown that the combination of microwave-assisted foam and hexamethylenetetramine as a fuel allows us to produce metallic Co nanoparticles with the broad size distribution (∼5-40 nm), high coercivity (370 Oe), and high value of saturation magnetization (137 emu/g) by the one-step solution combustion synthesis under normal air atmosphere without any post reduction.
Abstract:In this work, CoFe2O4@SiO2@TiO2 core-shell magnetic nanostructures have been prepared by coating of cobalt ferrite nanoparticles with the double SiO2/TiO2 layer using metallorganic precursors. The Transmission Electron Microscopy (TEM), Energy Dispersive X-Ray Analysis (EDX), Vibrational Sample Magnetometer (VSM) measurements and Raman spectroscopy results confirm the presence both of the silica and very thin TiO2 layers. The core-shell nanoparticles have been sintered at 600 °C and used as a catalyst in photo-oxidation reactions of methylene blue under UV light. Despite the additional non-magnetic coatings result in a lower value of the magnetic moment, the particles can still easily be retrieved from reaction mixtures by magnetic separation. This retention of magnetism was of particular importance allowing magnetic recovery and re-use of the catalyst.
Magnetic,
optical, and structural properties of superparamagnetic
CoFe2O4 nanoparticles (MNPs), both isolated
and in aggregates, are investigated by magnetic circular dichroism
(MCD) spectroscopy. The MCD signal for MNPs is more than an order
of magnitude greater than the signal for organic molecules, therefore
making this technique a very sensitive tool for the examination of
MNP properties. MNP aggregation had a distinct effect upon the MCD
signal intensity. Correlation between MCD signal intensity and MNP
magnetization shows that MNP aggregation in colloidal solutions results
in the changing of MNP magnetization with a maximum at the mean aggregate
size of approximately 100 nm.
We demonstrate a new strategy to inhibit and trigger polymerisation of an adhesive formulation, utilising colloidal core@shell CoFe2O4@MnO2 magnetic nanoparticles.
Here we report a low cost scalable synthesis of L‐alanine capped CoFe2O4 magnetic nanoparticles, with excellent size tunability and magnetic properties. Samples were analyzed in details using electron microscopy, X‐ray powder diffraction and vibrational sample magnetometry. The magnetic nanoparticles have demonstrated excellent size distribution, uniformity and phase purity. It was found that the presence and concentration of L‐alanine ligand dramatically affects the size and morphology of the resulting CoFe2O4 nanoparticles, enabling size tunability from 120.5 to 11.3 nm. The magnetic moments of nanomaterials are ranging from 74 to 41 Am2kg−1, they are easily manipulated by an external magnetic field and show the onset of superparamagnetic behavior in the smaller nanoparticles prepared.
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