| 1. |
- Almessiere, M. A., et al.
(författare)
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Review on functional bi-component nanocomposites based on hard/soft ferrites : Structural, magnetic, electrical and microwave absorption properties
- 2021
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Ingår i: Nano-Structures and Nano-Objects. - : Elsevier B.V.. - 2352-507X. ; 26
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Tidskriftsartikel (refereegranskat)abstract
- Bi-component hard (H) (hexaferrite) and soft (S) (spinel) ferrites nanocomposites are gaining interest scientifically and technically, not only for combining the high magnetization of spinel ferrite nanomaterials and the high coercivity of hexaferrite magnetic nanomaterials but also for the outstanding exchange-coupling behavior among hard and soft magnetic phase. The improved magnetic features lead to produce a new nanocomposite with higher microwave absorption capacity in comparison with ferrites with a single absorption mechanism. Exchange-coupled effect has a potential application based on microwave absorption, recording media, permanent magnets, biomedical and other applications. Intensive studies have been conducted on this topic to produce hard/soft (H/S) ferrite nanocomposites with establishment of exchange coupled effect between the two phases. Preparation methods, microstructure, magnetics features, microwave and dielectric properties, and applications are elaborated. Consequently, a comprehensive effort has been made to contain an original reference investigating in detail the precise outcomes of the published papers.
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| 2. |
- Gopakumar, Deepu A., et al.
(författare)
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Carbon dioxide plasma treated PVDF electrospun membrane for the removal of crystal violet dyes and iron oxide nanoparticles from water
- 2019
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Ingår i: Nano-Structures and Nano-Objects. - : Elsevier BV. - 2352-507X. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Here we reported a reactive plasma treatment of polyvinylidene fluoride (PVDF) electrospun membrane by using carbon dioxide (CO 2 ) plasma in order to reduce the hydrophobicity of the PVDF membrane and thereby used to remove toxic crystal violet dye (CV) and iron oxide (Fe 2 O 3 ) nanoparticles from water. The demonstrated plasma treated PVDF electrospun membrane showed a decrement in the hydrophobicity after plasma treatment. Most of the microfiltration membranes based on PVDF were fabricated via phase inversion technique and solvent casting. The main drawback of these methods is that to obtain membranes with uniform pore size. Moreover, the membranes fabricated via phase inversion and solvent casting process have low surface area whereas in the membranes via electrospinning technique have interconnected pore structure with high surface area and uniform pore size. The contact angle of the neat PVDF electrospun membrane and plasma treated PVDF electrospun membrane were 141°and 102°respectively. FTIR studies revealed that, after CO 2 plasma treatment, highly negative carboxylate (COO-) groups were formed on the surface of the PVDF electrospun membrane. With the 10 mg/L of crystal violet (CV) aqueous solution, the dye adsorption capacity was 1.368 mg/g of the membrane for neat PVDF membrane and 3.84 mg/g of the membrane for plasma treated PVDF membrane. It was found that, the CO 2 plasma treated PVDF membrane had two- or three-times greater adsorption capacity then neat PVDF membrane against crystal violet dyes which was due to the strong electrostatic interaction between the highly negative carboxyl groups on the surface of plasma treated PVDF electrospun membrane and protonated CV dye. Both neat PVDF membrane and plasma treated PVDF membrane showed excellent filtration capacity against Fe 2 O 3 nanoparticles. The demonstrated plasma treated PVDF membrane could successfully remove iron oxide nanoparticles and crystal violet dyes from water via size exclusion and adsorption mechanism respectively.
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| 3. |
- Haiduk, Yulyan, et al.
(författare)
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WO3–graphene–Cu nanocomposites for CO, NO2 and acetone gas sensors
- 2022
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Ingår i: Nano-Structures & Nano-Objects. - : Elsevier BV. - 2352-507X. ; 29, s. 100824-
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Tidskriftsartikel (refereegranskat)abstract
- The control of indoor air quality and the detection of toxic gases and volatile organic compounds are important tasks for improving life and work conditions, and are highly demanded in a variety of industrial, agricultural and environmental applications. This requires the development of special gas sensing materials with a high sensing response to a variety of gases of a different chemical nature. Herein we report a study on the synthesis, characterization and investigation of the gas sensing properties of WO3 -graphene–Cu composite nanomaterials. The nanomaterials have a closely interconnected defective structure with developed surfaces and are characterized by an enhanced sensing response to CO, NO2 and acetone. The composite nanomaterials with WO3 crystallite sizes of 13–17 nm were synthesized by a modified sol–gel method, where pre-synthesized graphene@Cu nanopowder, obtained by the solution combustion method, was added into an H2WO4 gel before the xerogel formation stage. The graphene@Cu flakes played the role of the centers of WO3 crystallite nucleation, leading to the formation of mutually interconnected crystalline structures. The graphene@Cu composite tends to accumulate on the tungsten oxide surfaces, causing the formation of structural defects, influencing the surface energy state and concentration of free electrons. The concentration of defects decreases with the increase of graphene@Cu from 1 to 4 wt%, which also affects the gas sensing properties of the WO3-graphene@Cu composites. The highest sensing response to CO and acetone of 19.7 and 21.4, respectively, were detected for the composite with 1 wt% of graphene@Cu. The composite with 2 wt.% of graphene@Cu additive showed the highest sensing response to NO2.
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| 4. |
- Jamshidi Zavaraki, Asghar, et al.
(författare)
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Solar cell sensitized with “green” InP-ZnS quantum dots : Effect of ZnS shell deposition
- 2020
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Ingår i: Nano-Structures and Nano-Objects. - : Elsevier BV. - 2352-507X. ; 22
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Tidskriftsartikel (refereegranskat)abstract
- Colloidal InP and ZnS-coated InP quantum dots (QDs) were synthesized by hot injection method and successfully employed as sensitizer for the first time in quantum dot sensitized solar cells (QDSSCs). Colloidal InP QDs has not been used in QDSSCs due to low stability and high sensitivity to the moisture. In this work ZnS-coating were applied as a strategy to increase the stability and protect InP against moisture and interaction with electrolyte. The nature of low toxicity of such QDs compared to high toxic Cd-based QDs was the main idea to employ “green” and heavy metal-free InP-ZnS QDs for future solar cell application. It is found that ZnS shell-coating caused the absorption onset to shift toward longer wavelength and broader absorption. In the solar cell device, ZnS shell not only acts as protection agent and increases the life time for InP QDs but also enhances the power conversion efficiency by more than 2 times.
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| 5. |
- Khort, Aliaksandr, et al.
(författare)
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Solution combustion synthesis of single-phase bimetallic nanomaterials
- 2021
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Ingår i: Nano-Structures & Nano-Objects. - : Elsevier BV. - 2352-507X. ; 26
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Tidskriftsartikel (refereegranskat)abstract
- Solution combustion synthesis approach with hexamethylenetetramine/citric acid as mixed fuel was used for the synthesis of bimetallic single-phase nanomaterials in CoCu, CoNi, CoFe, and FeNi systems in the air. All obtained nanomaterials are characterized by fine crystallinity with crystallites sizes from 15 nm to 41 nm. The study shows the using mixed fuel in the synthesis approach allows obtaining CoNi and CoFe bimetallic phase, as synthesis in CoCu and FeNi systems results in obtaining split phases. Due to its higher stability in solutions the mixed fuel could be used for industrial scale-up of the solution combustion production of the polymetallic nanomaterials.
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| 6. |
- Roslyakov, Sergey, et al.
(författare)
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One-step solution combustion synthesis of nanostructured transition metal antiperovskite nitride and alloy
- 2021
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Ingår i: Nano-Structures and Nano-Objects. - : Elsevier. - 2352-507X. ; 28
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Tidskriftsartikel (refereegranskat)abstract
- Multicomponent transition metal-based nanomaterials (MTMAs) are of interest to the materials science community because of their structure-tunable properties. However, it is challenging to support the phase stabilization and homogeneous distribution of the constituent elements within a single phase. Herein, we report the successful one-step combustion syntheses of a novel quaternary antiperovskite nitride, (Co0.33Cu0.33Ni0.33)4N, and a ternary CoCuNi alloy as examples of MTMAs. The synthesized nanomaterials have hollow spherical and sponge-like morphologies. We also share the results of a study of the parameters that influence the alloy and nitride phase formation and discuss possible mechanisms for the combustion synthesis of the MTMAs. It was established that the synthesis approach as well as adjusting the environment conditions created through the main synthesis parameters, including molar φ ratio, furnace temperature (Tfurn) and carrier gas flow rate, are the key characteristics responsible for the formation and stabilization of specific phase composition and morphology of the final product. The optimal parameters for the ternary CoCuNi alloy synthesis by sol–gel combustion were φ in the range of 1.25–1.5. The stoichiometric (Co0.33Cu0.33Ni0.33)4N phase stabilizes during a spray combustion synthesis with φ = 3, Tfurn = 900 °C and a flow rate of 4 L/min. The produced alloy possesses a high saturation magnetization of 74 emu/g, while the nitride retains only 11 emu/g. The study of the nitride phase’s hydrogenation reaction showed ∼96 % efficiency of NH3 evolution (3.797 mmol/g).
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