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.

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.

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.

Optical and Magnetic Studies of Fe3O4/Au Core/Shell Nanocomposites

2019 ◽  
Vol 18 (05) ◽  
pp. 1850033 ◽  
Author(s):  
Al-Sayed A. M. Al-Sherbini ◽  
Gamal El-Ghannam ◽  
Hesham Yehya ◽  
O. Aied Nassef
Keyword(s):  
Shell Structures ◽  
Core Shell ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Visible Absorption ◽  
The Core ◽  
Transmission Electron ◽  
Surface Poisoning ◽  
Shell Particles

In this paper, we report the synthesis of Fe3O4 nanoparticles which are resistant to surface poisoning, has been adopted. Fe3O4 nanoparticles have been successfully coated with Au in the form of a shell with different sizes (Fe3O4/Au Core/Shell). Adjustment of the components’ ratio makes the shell thickness of the core/shell particles tunable. Thus, the presented route yields well-defined core/shell structures of different sizes in the range 15–57[Formula: see text]nm with varying the proportion of Au noble metal to Fe3O4 nanoparticles. The UV-Visible absorption spectra, X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) were applied for the characterization of the formed core/shell structures. Moreover, magnetic properties of the core/shell nanocomposites were also studied using Vibrating Sample Magnetometry (VSM).

The formation of colloidal copper nanoparticles stabilized by zinc stearate: one-pot single-step synthesis and characterization of the core–shell particles

2009 ◽  
Vol 11 (37) ◽  
pp. 8358 ◽  
Author(s):  
André Rittermeier ◽  
Shaojun Miao ◽  
Marie K. Schröter ◽  
Xiaoning Zhang ◽  
Maurits W. E. van den Berg ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Single Step ◽  
Zinc Stearate ◽  
Synthesis And Characterization ◽  
Core Shell ◽  
One Pot ◽  
The Core ◽  
Shell Particles

The Microemulsion Method for Preparing TiO2 Coated SiO2 Core-Shell Particles

2014 ◽  
Vol 602-603 ◽  
pp. 59-62
Author(s):  
Jing Xie ◽  
Le Fu Mei ◽  
Li Bing Liao ◽  
Guo Cheng Lv ◽  
Zhi Guo Xia ◽  
...  
Keyword(s):  
Shell Structure ◽  
Sintering Temperature ◽  
Phase Changes ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Core Shell Structure ◽  
Shell Particles ◽  
Morphology Changes

In this paper, the monodisperse TiO2 particles and TiO2 coated SiO2 core-shell particles were prepared by the method of microemulsion, and the phase and morphology of TiO2 and TiO2 coated SiO2 core-shell structure particles were analyzed by using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). At the same time, the phase changes and morphology changes of the two different kinds of structural particles as the changes of sintering temperature were compared. The results show that when the TiO2 particles were prepared by the method of microemulsion, the content of anatase TiO2 decreased gradually and the rutile TiO2 increased gradually as the sintering temperature increases from 550 °C to 650 °C; the core-shell particles of TiO2 coated SiO2 prepared were anatase when the sintering temperature increases from 600 °C to 800 °C; all of the particles size were about 1μm, the monodispersity of the particles were optimal and the particles were coated evenly, smoothly. Keywords: TiO2; SiO2; core-shell structure

Synthesis and Characterization of Monodisperse Spherical SiO2@Y2O3: Tb3+ Particles with Core-Shell Structure

2014 ◽  
Vol 997 ◽  
pp. 317-320 ◽  
Author(s):  
Huan Wang ◽  
Ya Bing Liu ◽  
Ling Wei Kong
Keyword(s):  
Smooth Surface ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Spherical Shape ◽  
Core Shell ◽  
The Core ◽  
Sol Gel Process ◽  
Shell Particles ◽  
Average Size

Spherical submicron SiO2 particles have been coated with luminescent Y2O3: Tb3+ layers by a Pechini sol-gel process, resulting in the formation of SiO2@Y2O3: Tb3+ core-shell particles. The obtained core–shell phosphors have perfect spherical shape with narrow size distribution (average size ca. 450 nm), smooth surface and non-agglomeration. The thickness of shells could be easily controlled by changing the number of deposition cycles (35 nm for two deposition cycles). Under the excitation of ultraviolet, the Tb3+ ion mainly shows its characteristic emissions in the core-shell particles from Y2O3: Tb3+) shells. The emission intensity of Tb3+ can be tuned by the annealing temperature and the number of coating cycles.

Novel Preparation of Silver-Coated Copper in Aqueous Solution

2010 ◽  
Vol 658 ◽  
pp. 173-176
Author(s):  
Yong Hui Song ◽  
Ting Su ◽  
Yong Yang ◽  
Xin Zhe Lan ◽  
Huan Zhan
Keyword(s):  
Hydrazine Hydrate ◽  
Active Sites ◽  
Room Temperature ◽  
Spherical Particles ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Copper Powders ◽  
Shell Particles

Hollow and solid spherical silver-coated copper powders with size of 1μm were facilely prepared by the reduction of silver nitrate in the polyvinyl pyrrolidone (PVP) dispersed copper hydrosol solution at room temperature in the presence of hydrazine hydrate. Scanning electron microscopy and X-ray diffraction were conducted to investigate the formation process of silver-coated copper core-shell particles. The results showed that the absorption and deposition of the Ag nuclei initially occurred at the active sites on the core surfaces as seeds which urged the further deposition of silver species to form sprinkled-structure core-shell particles. During the growth of the silver shell, the dissolution of copper core would result in the formation of hollow spherical particles, while the hydrazine hydrate would help to generate the solid spherical silver-coated copper powders.

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