In situ ultrasound-assisted preparation of Fe 3 O 4 @MnO 2 core-shell nanoparticles integrated with ion co-precipitation for multielemental analysis by total reflection X-ray fluorescence

A biomimetic and facile approach for integrating Fe 3 O 4 and Au with polydopamine (PDA) was proposed to construct gold-coated Fe 3 O 4 nanoparticles ( Fe 3 O 4@ Au – PDA ) with a core–shell structure by coupling in situ reduction with a seed-mediated method in aqueous solution at room temperature. The morphology, structure and composition of the core–shell structured Fe 3 O 4@ Au – PDA nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectrometry (XPS). The formation process of Au shell was assessed using a UV-Vis spectrophotometer. More importantly, according to investigating changes in PDA molecules by Fourier transform infrared spectroscopy (FTIR) and in preparation process of the zeta-potential data of nanoparticles, the mechanism of core–shell structure formation was proposed. Firstly, PDA-coated Fe 3 O 4 are obtained using dopamine (DA) self-polymerization to form thin and surface-adherent PDA films onto the surface of a Fe 3 O 4 "core". Then, Au seeds are attached on the surface of PDA-coated Fe 3 O 4 via electrostatic interaction in order to serve as nucleation centers catalyzing the reduction of Au 3+ to Au 0 by the catechol groups in PDA. Accompanied by the deposition of Au , PDA films transfer from the surface of Fe 3 O 4 to that of Au as stabilizing agent. In order to confirm the reasonableness of this mechanism, two verification experiments were conducted. The presence of PDA on the surface of Fe 3 O 4@ Au – PDA nanoparticles was confirmed by the finding that glycine or ethylenediamine could be grafted onto Fe 3 O 4@ Au – PDA nanoparticles through Schiff base reaction. In addition, Fe 3 O 4@ Au – DA nanoparticles, in which DA was substituted for PDA, were prepared using the same method as that for Fe 3 O 4@ Au – PDA nanoparticles and characterized by UV-Vis, TEM and FTIR. The results validated that DA possesses multiple functions of attaching Au seeds as well as acting as both reductant and stabilizing agent, the same functions as those of PDA.

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Insitu ultrasound-assisted synthesis of Fe3O4 nanoparticles with simultaneous ion co-precipitation for multielemental analysis of natural waters by total reflection X-ray fluorescence spectrometry

Journal of Analytical Atomic Spectrometry ◽

10.1039/c3ja50067e ◽

2013 ◽

Vol 28 (6) ◽

pp. 923 ◽

Cited By ~ 19

Author(s):

Vanesa Romero ◽

Isabel Costas-Mora ◽

Isela Lavilla ◽

Carlos Bendicho

Keyword(s):

Fe3o4 Nanoparticles ◽

Natural Waters ◽

Total Reflection ◽

Fluorescence Spectrometry ◽

X Ray ◽

Multielemental Analysis ◽

Ultrasound Assisted ◽

Co Precipitation

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Thermally induced transformations of Au@Cu2O core–shell nanoparticles into Au–Cu nanoparticles from temperature-programmed in situ powder X-ray diffraction

Journal of Applied Crystallography ◽

10.1107/s1600576719004497 ◽

2019 ◽

Vol 52 (3) ◽

pp. 579-586 ◽

Cited By ~ 4

Author(s):

Robert Koch ◽

Guangfang Li ◽

Shubham Pandey ◽

Simon Phillpot ◽

Hui Wang ◽

...

Keyword(s):

Crystal Growth ◽

Core Shell ◽

X Ray Diffraction ◽

Shell Nanoparticles ◽

Thermally Induced ◽

X Ray ◽

Cu Content ◽

Temperature Programmed ◽

Core Shell Nanoparticles

Temperature-programmed in situ X-ray diffraction with whole-powder-pattern modeling is used to investigate the reaction of Au@Cu2O core–shell nanoparticles to form nanocrystalline bimetallic Cu x Au1−x alloys (x = 0, 0.25, 0.5, 0.75, 1.0) in a reducing atmosphere. The mechanisms of the reactions are key to informed design of tailored non-equilibrium nanostructures for catalytic and plasmonic materials. The Au@Cu2O reaction is initiated by reduction of the Cu2O cuprite shell to form nanocrystalline metallic Cu at about 413 K. Alloying begins immediately upon formation of metallic Cu at 413 K, with the nucleation of an Au-rich alloy phase which reaches the nominal Cu content of the overall system stoichiometry by 493 K. All bimetallic alloys form a transient ordered Cu3Au intermetallic compound at intermediate temperatures, with the onset of ordering and subsequent disordering varying by composition. No evidence for an ordered Au3Cu intermetallic is found for any composition. Significant crystal growth in the bimetallic phase is apparent at higher temperatures, with the onset temperature increasing with Cu concentration and initial Cu-shell thickness. The reduction of the cuprite phase is slowed by the presence of the core–shell interface, and crystal growth in the Cu shell is completely suppressed within the alloy systems.

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Synthesis and Advanced Characterization of Polymer-Protein Core-Shell Nanoparticles

Catalysts ◽

10.3390/catal11060730 ◽

2021 ◽

Vol 11 (6) ◽

pp. 730

Author(s):

Erik Sarnello ◽

Tao Li

Keyword(s):

Particle Size ◽

Small Angle ◽

Core Shell ◽

Assembly Process ◽

Shell Nanoparticles ◽

X Ray ◽

X Ray Scattering ◽

Wide Range ◽

Core Shell Nanoparticles ◽

Ray Scattering

Enzyme immobilization techniques are widely researched due to their wide range of applications. Polymer–protein core–shell nanoparticles (CSNPs) have emerged as a promising technique for enzyme/protein immobilization via a self-assembly process. Based on the desired application, different sizes and distribution of the polymer–protein CSNPs may be required. This work systematically studies the assembly process of poly(4-vinyl pyridine) and bovine serum albumin CSNPs. Average particle size was controlled by varying the concentrations of each reagent. Particle size and size distributions were monitored by dynamic light scattering, ultra-small-angle X-ray scattering, small-angle X-ray scattering and transmission electron microscopy. Results showed a wide range of CSNPs could be assembled ranging from an average radius as small as 52.3 nm, to particles above 1 µm by adjusting reagent concentrations. In situ X-ray scattering techniques monitored particle assembly as a function of time showing the initial particle growth followed by a decrease in particle size as they reach equilibrium. The results outline a general strategy that can be applied to other CSNP systems to better control particle size and distribution for various applications.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.306-307.410 ◽

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. FeSO47H2O and NaBH4 were respectively dissolved in distilled water, then moderated Fe3O4 particles and surfactant(PVP) were ultrasonic dispersed into the FeSO47H2O 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.

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Core-Shell SiO2/Ag Composite Spheres Prepared by Electrical Exploding Wire Plasma Technique: Synthesis and Characterization

NeuroQuantology ◽

10.14704/nq.2021.19.10.nq21161 ◽

2021 ◽

Vol 19 (10) ◽

pp. 82-88

Author(s):

Duaa A. Uamran ◽

Qasim Hassan Ubaid ◽

Hammad R. Humud

Keyword(s):

Laser Pulse ◽

Laser Pulses ◽

Structural Features ◽

Optical Absorption Spectroscopy ◽

Core Shell ◽

X Ray Diffraction ◽

Shell Nanoparticles ◽

X Ray ◽

Photocatalytic Activities ◽

Core Shell Nanoparticles

Core-shell nanoparticles (SiO2/Ag) were manufactured by using a two-step process: Electric detonation of Ag. Wire in colloidal solution particles then by using laser pulses, nanoparticles are released. The structural features of these nanoparticles were checked by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The (XRD) study showed the progressive coverage of SiO2/Ag by nanoparticles according to the energies of the laser pulse. Measurements of morphology and EDX confirmed the Core/shell structure with particle size at the nano level. It confirmed that preliminary analysis consists of a SiO2 core and an Ag shell from FESEM. The surface of the microscopic balls (SiO2) has been covered completely and homogeneously with Ag nanoparticles, Moreover, Ultraviolet-Visible, and by optical absorption spectroscopy, the Nanoparticles with core crust SiO2/Ag showed excellent photocatalytic activities at various concentrations and laser pulse energy.

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