The magnetic nanopowders can be potentially applied in wide range of fields such as magnetic storage, magnetic fluid, medical diagnosis, conducting paints, rechargeable batteries, optoelectronics, ...magnetic recording media, drug delivery system and catalysis. They have attracted interest in the past decade and have also been studied extensively because of their size- and shape-dependent physical-chemical and magnetic properties for applications in various useful technologies. In this work, we present our experimental results on the preparation of nanosized Ni nanoparticles with different shapes by using a wet chemical solution route. Ni nanoparticles were prepared by reducing a Ni-complex formed between nickel-acetate and hydrazine solution under basic condition. Then through the control of reaction temperature and ageing time, nanosized Ni particles with different morphologies could be formed. The morphology and sizes of synthesized nanostructures were studied by scanning electron microscopy (SEM). Structural properties of nanoparticles were examined by X-ray diffraction. We also report the core-shell structures of micro-composites of silica-nickel (SiO2/Ni). The composite core-shell structures were formed by the control of the surface charges of particles in aqueous solutions. A specific composite (SiO2/Ni) can be produced by controlling the surface charge, the pH and the molar ratio of the components. Core-shell structures are stable at room temperature.
The rheological properties of two non-polar liquids silicone oil or perfluorinated oil (FC70) containing various types of particles, barium titanate, nickel and iron oxide, were investigated as ...functions of solid loading, particle size and shear rate. All the particles were synthesised in-house. The viscosities of either silicone oil or FC70 containing different solid loadings (10, 20 and 30 g/L) were measured over the shear rate range of 0.10–10 s
−1
. All the nanofluids showed shear-thinning behaviour within this range and the viscosities increased with the increase of concentrations of nanoparticle and with the decrease of particle size. The highest increase of viscosity was found to be caused by nickel particles in silicone oil due to the formation of Ni network.
Nanocoatings on micro- or nanoparticles Libor, Z.; Zhang, Q.; Israel, C. ...
Materials science and technology,
11/1/2009, 20091100, 2009-11-00, 20091101, Volume:
25, Issue:
11
Journal Article
Peer reviewed
Open access
In recent years, coating processes with nanoparticles have been investigated for the development of nanostructured materials. In this work, the authors report the core shell structures of ...microcomposites of SiO
2
/Ni and SiO
2
/Fe
3
O
4
and nanocomposites of BaTiO
3
/Fe
3
O
4
and PZT/Fe
3
O
4
. These composites were prepared by an aqueous chemical synthesis method and characterised by SEM, XRD, EDX analysis and vibrating sample magnetometry before and after incorporation into the core shell structure. The composite core shell structures were formed by the control of the surface charges of particles in aqueous solutions. A specific composite (SiO
2
/Ni, SiO
2
/Fe
3
O
4
and BaTiO
3
/Fe
3
O
4
and PZT/Fe
3
O
4
nanocomposites) can be produced by controlling the pH and the molar ratio of components. These magnetic composites can be potentially applied in wide range of fields such as microreactors, delivery vehicle systems, drug delivery systems and multiferroics.
Aggregation and dispersion of mineral particles spontaneously take place under changing environmental conditions in natural systems. The structure of particle network in soils, the retardation or ...release of colloidal particles, and their mobility and transport are inherently influenced by natural organic matter bound to the mineral matrix. Since the surface properties of clay mineral and metal oxide particles, and the electrified mineral–water interfaces play a major role in formation, structure and strength of aggregates, any surface modification, especially by polyanionic organic complexants such as humic substances, has a significant affect on particle interaction in a mineral assemblage. The permanently and/or conditionally charged clay minerals (montmorillonite and kaolinite) and iron oxides (hematite and magnetite), as known major mineral components in natural waters, were selected for studying their surface charge characteristics and pH dependent interactions. We discuss how the surface charge correlates with particle aggregation through some characteristic examples for homo and heterocoagulation of similar and dissimilar mineral particles under acidic condition (at pH ∼4) in the dilute and concentrated systems studied by means of light scattering and rheology, respectively. The adsorption of a brown coal derived humic acid, and its influence on the surface charge character and particle aggregation of clay and iron oxide particles were also studied in dilute and concentrated suspensions. Humic acids can be bound to the most reactive surface sites of clay and oxide particles, i.e. to
Al
-OH mainly at the edges of clay lamellae, and to
Fe
-OH on iron oxides, in surface complexation reaction, therefore their role in particle aggregation is specific. Relations between surface complexation, surface charge modification, and particle aggregation in pure and mixed montmorillonite–iron oxide systems are explained.
The magnetic nanopowders can be potentially applied in wide range of fields such as magnetic storage, magnetic fluid, medical diagnosis, conducting paints, rechargeable batteries, optoelectronics, ...magnetic recording media, drug delivery system and catalysis. They have attracted interest in the past decade and have also been studied extensively because of their size- and shape-dependent physical-chemical and magnetic properties for applications in various useful technologies. In this work, we present our experimental results on the preparation of nanosized Ni nanoparticles with different shapes by using a wet chemical solution route. Ni nanoparticles were prepared by reducing a Ni-complex formed between nickel-acetate and hydrazine solution under basic condition. Then through the control of reaction temperature and ageing time, nanosized Ni particles with different morphologies could be formed. The morphology and sizes of synthesized nanostructures were studied by scanning electron microscopy (SEM). Structural properties of nanoparticles were examined by X-ray diffraction. We also report the core-shell structures of micro-composites of silica-nickel (SiO sub(2)/Ni). The composite core-shell structures were formed by the control of the surface charges of particles in aqueous solutions. A specific composite (SiO sub(2)/Ni) can be produced by controlling the surface charge, the pH and the molar ratio of the components. Core-shell structures are stable at room temperature.
The magnetic nanopowders can be potentially applied in wide range of fields such as magnetic storage, magnetic fluid, medical diagnosis, conducting paints, rechargeable batteries, optoelectronics, ...magnetic recording media, drug delivery system and catalysis. They have attracted interest in the past decade and have also been studied extensively because of their size- and shape-dependent physical-chemical and magnetic properties for applications in various useful technologies. In this work, we present our experimental results on the preparation of nanosized Ni nanoparticles with different shapes by using a wet chemical solution route. Ni nanoparticles were prepared by reducing a Ni-complex formed between nickel-acetate and hydrazine solution under basic condition. Then through the control of reaction temperature and ageing time, nanosized Ni particles with different morphologies could be formed. The morphology and sizes of synthesized nanostructures were studied by scanning electron microscopy (SEM). Structural properties of nanoparticles were examined by X-ray diffraction. We also report the core-shell structures of micro-composites of silica-nickel (SiO
2/Ni). The composite core-shell structures were formed by the control of the surface charges of particles in aqueous solutions. A specific composite (SiO
2/Ni) can be produced by controlling the surface charge, the pH and the molar ratio of the components. Core-shell structures are stable at room temperature.
Bulk 0.7PbZr0.52Ti0.48O3–0.3NiFe2O4 nanoceramic composites with a grain size of ~50 nm were fabricated using chemical synthesis, high‐energy ball‐milling, and spark plasma sintering. The composite ...produced broad dielectric constant peaks and frequency dispersion, similar to relaxor ferroelectrics, and was ferroelectric and ferromagnetic. The dielectric and piezoelectric properties of nanoceramics are lower than those of microceramics due to grain‐size effects. “Butterfly”‐type magnetoelectric (ME) loops indicate that direct stress coupling between magnetostrictive and piezoelectric phases is still active in composite ceramics when the grain size is ~50 nm.
The majority of harmful atmospheric CO and NOx emissions are from vehicle exhausts. Although there has been success addressing NOx emissions at temperatures above 250 °C with selective catalytic ...reduction technology, emissions during vehicle cold start (when the temperature is below 150 °C), are a major challenge. Herein, we show we can completely eliminate both CO and NOx emissions simultaneously under realistic exhaust flow, using a highly loaded (2 wt %) atomically dispersed palladium in the extra‐framework positions of the small‐pore chabazite material as a CO and passive NOx adsorber. Until now, atomically dispersed highly loaded (>0.3 wt %) transition‐metal/SSZ‐13 materials have not been known. We devised a general, simple, and scalable route to prepare such materials for PtII and PdII. Through spectroscopy and materials testing we show that both CO and NOx can be simultaneously completely abated with 100 % efficiency by the formation of mixed carbonyl‐nitrosyl palladium complex in chabazite micropore.
Loaded: The majority of harmful atmospheric CO and NOx emissions are from vehicle exhausts. Both CO and NOx emissions can be simultaneously removed under realistic exhaust flow, using highly loaded (2 wt %) atomically dispersed palladium in the extra‐framework positions of a small‐pore chabazite zeolite material. To do this, a simple and scalable route to highly loaded Pd and Pt small‐pore siliceous zeolites is developed.
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