Synthesis of Al/Cu core–shell particles through optimization of galvanic replacement method in alkaline solution

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Rashid Ali ◽  
Fahad Ali ◽  
Aqib Zahoor ◽  
Rub Nawaz Shahid ◽  
Naeem ul HaqTariq ◽  
...  
Keyword(s):  
Alkaline Solution ◽  
Copper Deposition ◽  
Molar Ratio ◽  
Galvanic Replacement ◽  
Core Shell ◽  
Affecting Factors ◽  
X Ray ◽  
Replacement Method ◽  
Al Powder ◽  
Shell Particles

Abstract In this work, Al/Cu core–shell particles were successfully synthesized through an optimized galvanic replacement method. For this purpose, a uniform and dense copper layer was deposited on aluminum particles in an alkaline solution. The effects of four deposition factors, i. e. (i) molar ratio EDTA-2Na/CuSO4 · 5H2O, (ii) molar ratio CuCl2/Al powder, (iii) pH and (iv) temperature were systematically studied and optimized using the Taguchi orthogonal (L9) method. It was observed that molar ratio EDTA-2Na/CuSO4 · 5H2O and temperature are the most affecting factors in the deposition process. By increasing their levels, copper deposition increases within a specified time. The X-ray diffraction and scanning electron microscopy/ energy-dispersive X-ray spectroscopy results revealed the formation of homogeneous nanostructured Cu shells around Al particles. The results revealed that to achieve maximum copper deposition on Al powder; molar ratio EDTA-2Na. 2H2O/CuSO4. 5H2O, molar ratio CuCl2/Al powder, pH and temperature of the deposition bath should be 2.0, 0.05, 8.8 and 55 °C, respectively.

Monodisperse Fe3O4/Fe Core/Shell Nanoparticles with Enhanced Magnetic Property

2011 ◽  
Vol 306-307 ◽  
pp. 410-415
Author(s):  
Li Sun ◽  
Fu Tian Liu ◽  
Qi Hui Jiang ◽  
Xiu Xiu Chen ◽  
Ping Yang
Keyword(s):  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Shell Nanoparticles ◽  
X Ray ◽  
Transmission Electron ◽  
Shell Particles ◽  
Core Shell Nanoparticles

Core/shell type nanoparticles with an average diameter of 20nm were synthesized by chemical precipitation method. Firstly, Monodisperse Fe3O4 nanoparticles were synthesized by solvethermal method. FeSO4ž7H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO4ž7H2O solution. The resulting solution was stirred 2 h at room temperature. Fe could be deposited on the surface of monodispersed Fe3O4 nanoparticles to form core-shell particles. The particles were characterized by using various experimental techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), AGM and DTA. The results suggest that the saturation magnetization of the nanocomposites is 100 emu/g. The composition of the samples show monodisperse and the sides of the core/shell nanoparticles are 20-30nm. It is noted that the formation of Fe3O4/Fe nanocomposites magnetite nanoparticles possess superparamagnetic property.

scholarly journals Lead-Free BNT–BT0.08/CoFe2O4 Core–Shell Nanostructures with Potential Multifunctional Applications

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 672
Author(s):  
Marin Cernea ◽  
Roxana Radu ◽  
Harvey Amorín ◽  
Simona Gabriela Greculeasa ◽  
Bogdan Stefan Vasile ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Molar Ratio ◽  
Transmission Electron Microscopy Data ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Two Phase ◽  
X Ray ◽  
Shell Nanostructures

Herein we report on novel multiferroic core–shell nanostructures of cobalt ferrite (CoFe2O4)–bismuth, sodium titanate doped with barium titanate (BNT–BT0.08), prepared by a two–step wet chemical procedure, using the sol–gel technique. The fraction of CoFe2O4 was varied from 1:0.5 to 1:1.5 = BNT–BT0.08/CoFe2O4 (molar ratio). X–ray diffraction confirmed the presence of both the spinel CoFe2O4 and the perovskite Bi0.5Na0.5TiO3 phases. Scanning electron microscopy analysis indicated that the diameter of the core–shell nanoparticles was between 15 and 40 nm. Transmission electron microscopy data showed two–phase composite nanostructures consisting of a BNT–BT0.08 core surrounded by a CoFe2O4 shell with an average thickness of 4–7 nm. Cole-Cole plots reveal the presence of grains and grain boundary effects in the BNT–BT0.08/CoFe2O4 composite. Moreover, the values of the dc conductivity were found to increase with the amount of CoFe2O4 semiconductive phase. Both X-ray photoelectron spectroscopy (XPS) and Mössbauer measurements have shown no change in the valence of the Fe3+, Co2+, Bi3+ and Ti4+ cations. This study provides a detailed insight into the magnetoelectric coupling of the multiferroic BNT–BT0.08/CoFe2O4 core–shell composite potentially suitable for magnetoelectric applications.

Preparation of Core–Shell Silica Microspheres with Controllable Shell Thickness for Fast High Performance Liquid Chromatography Separation of Alkyl Benzenes and Intact Proteins

2021 ◽  
Vol 17 (3) ◽  
pp. 439-446
Author(s):  
Hongjun Xia ◽  
Huaiming Wang ◽  
Jianshan Wang ◽  
Lin Wang ◽  
Lin Jin ◽  
...  
Keyword(s):  
High Performance ◽  
Shell Thickness ◽  
Separation Efficiency ◽  
Molar Ratio ◽  
Etching Time ◽  
Core Shell ◽  
Silica Microspheres ◽  
Liquid Chromatography Separation ◽  
Shell Particles ◽  
Alkyl Benzenes

As it is difficult to prevent secondary nucleation and agglomeration during the preparation of core–shell silica microspheres, these issues have been successfully resolved in this study using template-dissolution-induced redeposition. The non-porous particles are transformed into core–shell silica microspheres (CSSMs) in the presence of cetyltrimethylammonium bromide and octyltrimethylammonium bromide under basic conditions. The shell thickness and pore sizes of the CSSMs are controlled by adjusting the etching time and molar ratio of the template, respectively. The CSSMs are modified using octadecyltrimethylammonium chloride to separate the mixture of alkyl benzenes, and a high column separation efficiency is achieved within two minutes. The CSSMs are used for the separation and analysis of proteins and the digests of bovine serum albumin. The chromatographic column packed with core–shell particles affords a significantly higher separation efficiency than the commercial column. Therefore, as a chromatographic stationary phase, these core–shell particles can potentially be used for the fast separation of proteins, small solutes, and complex samples.

X-ray Absorption Study of Structural Coupling in Photomagnetic Prussian Blue Analogue Core@Shell Particles

2014 ◽  
Vol 26 (8) ◽  
pp. 2586-2594 ◽  
Author(s):  
Daniel M. Pajerowski ◽  
Bruce Ravel ◽  
Carissa H. Li ◽  
Matthieu F. Dumont ◽  
Daniel R. Talham
Keyword(s):  
Prussian Blue ◽  
Core Shell ◽  
Absorption Study ◽  
Structural Coupling ◽  
Prussian Blue Analogue ◽  
X Ray ◽  
Shell Particles ◽  
X Ray Absorption

Preparation and Characterization of HGM-Ni0.5Co0.5Fe2O4 Core-Shell Particles by Homogeneous Coprecipitation

2013 ◽  
Vol 745-746 ◽  
pp. 293-297 ◽  
Author(s):  
Mei Yu ◽  
Jing Zhi Hu ◽  
Jian Hua Liu ◽  
Song Mei Li
Keyword(s):  
Spinel Ferrite ◽  
Magnetic Film ◽  
Core Shell ◽  
Chemical Compositions ◽  
Hollow Glass Microsphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coprecipitation Process ◽  
Shell Particles

HGM-Ni0.5Co0.5Fe2O4 core-shell particles were prepared by plating Ni0.5Co0.5Fe2O4 magnetic film on hollow glass microsphere (HGM) from the aqueous solution containing NiCl2·6H2O, FeCl2·4H2O, CoCl2·6H2O and HGMs without sintering. Urea was used as precipitator, and air was used as oxidizer in homogeneous coprecipitation process. The morphologies, phase structures, shell thickness, chemical compositions and magnetic performances of the core-shell particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and vibrating sample magnetometer (VSM), respectively. The results showed that a compact and continuous film with thickness at about 250 nm was coated on the HGM by the homogeneous coprecipitation process. The film was spinel ferrite phase, and was determined as the Ni0.5Co0.5Fe2O4. The saturation magnetization (Ms) and the coercivity (Hc) of as-synthesized HGM-Ni0.5Co0.5Fe2O4 core-shell particles were 20.886emu/g and 97.174G, respectively.

Effect of Calcination Temperature on the Morphology of Carbon Nanosphere Synthesized from Polymethylmethacrylate

2014 ◽  
Vol 974 ◽  
pp. 55-59 ◽  
Author(s):  
Abdullah F. Al-Ahmadi ◽  
Mohammed A. Al-Daous ◽  
Tawfik A. Saleh
Keyword(s):  
Calcination Temperature ◽  
Core Shell ◽  
Carbon Nanospheres ◽  
Batch Mode ◽  
Resorcinol Formaldehyde ◽  
X Ray ◽  
The Core ◽  
Shell Particles ◽  
Hollow Carbon

In this work, hollow carbon nanospheres (HCNs) were synthesized by carbonizing core/shell particles of polymethylmethacrylate (PMMA)/ resorcinol formaldehyde. The core/shell particles were prepared using emulsion polymerization; polymethylmethacrylate as a template and resorcinol-formaldehyde polymer as the carbon source. Spheres were first synthesized by batch mode polymerization and then the shell was polymerized on the surface of the spheres. The composite was stabilized, and then carbonized. The effect of calcination temperature was investigated in the range between 200-500oC. Scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDX), Raman and Fourier transform infrared (FTIR) were used for characterization of the resulting carbon.

scholarly journals Synthesis and Characterization of Core–Shell Magnetic Nanoparticles NiFe2O4@Au

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1075
Author(s):  
Diana Saykova ◽  
Svetlana Saikova ◽  
Yuri Mikhlin ◽  
Marina Panteleeva ◽  
Ruslan Ivantsov ◽  
...  
Keyword(s):  
Nickel Ferrite ◽  
Gold Deposition ◽  
Core Shell ◽  
X Ray ◽  
Gold Shell ◽  
Thick Gold ◽  
Synthesis Strategy ◽  
Vis Spectroscopy ◽  
Shell Particles ◽  
Average Size

In this study, NiFe2O4@Au core–shell nanoparticles were prepared by the direct reduction of gold on the magnetic surface using amino acid methionine as a reducer and a stabilizing agent simultaneously. The obtained nanoparticles after three steps of gold deposition had an average size of about 120 nm. The analysis of particles was performed by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectroscopy techniques. The results indicate successful synthesis of core–shell particles with the magnetic core, which consists of a few agglomerated nickel ferrite crystals with an average size 25.2 ± 2.0 nm, and the thick gold shell consists of fused Au0 nanoparticles (NPs). Magnetic properties of the obtained nanoparticles were examined with magnetic circular dichroism. It was shown that the magnetic behavior of NiFe2O4@Au NPs is typical for superparamagnetic NPs and corresponds to that for NiFe2O4 NPs without a gold shell. The results indicate the successful synthesis of core–shell particles with the magnetic nickel ferrite core and thick gold shell, and open the potential for the application of the investigated hybrid nanoparticles in hyperthermia, targeted drug delivery, magnetic resonance imaging, or cell separation. The developed synthesis strategy can be extended to other metal ferrites and iron oxides.

scholarly journals Design of Scorodite@Fe3O4 Core–Shell Materials and the Fe3O4 Shell Prevents Leaching of Arsenic from Scorodite in Neutral and Alkaline Environments

Coatings ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 523
Author(s):  
Yang Wang ◽  
Zhihao Rong ◽  
Xincun Tang ◽  
Shan Cao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Shell Structure ◽  
Molar Ratio ◽  
Alkaline Solutions ◽  
Arsenic Content ◽  
Core Shell ◽  
X Ray ◽  
Core Shell Structure ◽  
The Stability ◽  
Fe3o4 Core

In recent years, arsenic pollution has seriously harmed human health. Arsenic-containing waste should be treated to render it harmless and immobilized to form a stable, solid material. Scorodite (iron arsenate) is recognized as the best solid arsenic material in the world. It has the advantages of high arsenic content, good stability, and a low iron/arsenic molar ratio. However, scorodite can decompose and release arsenic in a neutral and alkaline environment. Ferroferric oxide (Fe3O4) is a common iron oxide that is insoluble in acid and alkali solutions. Coating a Fe3O4 shell that is acid- and alkali-resistant on the surface of scorodite crystals will improve the stability of the material. In this study, a scorodite@Fe3O4 core–shell structure material was synthesized. The synthesized core–shell material was detected by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman, and energy-dispersive X-ray spectroscopy (EDS) techniques, and the composition and structure were confirmed. The synthesis condition and forming process were analyzed. Long-term leaching tests were conducted to evaluate the stability of the synthesized scorodite@Fe3O4. The results indicate that the scorodite@Fe3O4 had excellent stability after 20 days of exposure to neutral and weakly alkaline solutions. The inert Fe3O4 shell could prevent the scorodite core from corrosion by the external solution. The scorodite@Fe3O4 core–shell structure material was suitable for the immobilization of arsenic and has potential application prospects for the treatment of arsenic-containing waste.

Preparation and Characterization of Gold-Loaded Magnetite/Silica Core-Shell Composites

2016 ◽  
Vol 42 ◽  
pp. 47-52
Author(s):  
Dan Dan Huang ◽  
Zhao Dai ◽  
Kun Yang ◽  
Yuan Yuan Chu
Keyword(s):  
Room Temperature ◽  
Solvothermal Reaction ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Transmission Electron ◽  
Silica Core ◽  
Shell Particles

The fabrication of gold-loaded magnetite/silica core-shell particles was presented in this paper. First, 250 nm of magnetic Fe3O4 nanoparticles were prepared by solvothermal reaction. Then, the Fe3O4 particles were coated by SiO2, and Au nanoparticles (AuNPs), respectively. The core-shell structure of these microspheres was confirmed by transmission electron microscopy (TEM) and Power X-ray diffraction (XRD). The magnetic property of the core-shell microspheres was investigated at room temperature. The results indicated that the core-shell composites had a well-retained high magnetic intensity, thus it can be easily separated from the mixture in less than a few minutes by simply using a magnet.

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