Synthesis and Characterization of Bimetallic Pd-Co Nano Magnetic Materials in Mesoporous Silica

2008 ◽  
Vol 1118 ◽  
Author(s):  
Balaji Tatineni ◽  
Dhananjay Kumar ◽  
Joslyn Perkins ◽  
Sergey Yarmolenko ◽  
Debasish Kuila
Keyword(s):  
Mesoporous Silica ◽  
Magnetic Measurements ◽  
Ammonium Bromide ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
One Pot ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Cetyl Trimethyl Ammonium ◽  
Co Nanoparticles

ABSTRACTAn one-pot procedure was developed for the synthesis of mesoporous silica containing bimetallic PdCo using Pd(NO3)2 and CoCl2, and cetyl trimethyl ammonium bromide (CTAB) as the templating agent, and tetramethoxy silane (TMOS) as the precursor. The materials were characterized using high resolution scanning transmission electron microscopy (HRSTEM), elemental analysis, X-ray diffraction (XRD), and magnetic measurements. The data indicate that the bimetallic Pd-Co nanoparticles are uniformly distributed on the inner pore walls of silica. The magnetic measurements of reduced Pd-Co nanoparticles (4-5 nm) in mesoporous silica reveal a typical ferromagnetic behavior up to 20 K and exhibit superparamagnetic properties above 30 K.

Synthesis and Structural Characterization of Ferromagnetic Au/Co Nanoparticles

2014 ◽  
Vol 1708 ◽  
Author(s):  
Nabraj Bhattarai ◽  
Subarna Khanal ◽  
Daniel Bahena ◽  
Robert L. Whetten ◽  
Miguel Jose-Yacaman
Keyword(s):  
Quantum Interference ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
Contrast Imaging ◽  
Uniform Size ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Co Nanoparticles ◽  
Z Contrast

ABSTRACTThe synthesis of bimetallic magnetic nanoparticles is very challenging because of the agglomeration and non-uniform size. In this paper, we present the synthesis of monodispersed 3-5 nm sized thiolated bimetallic alloyed Au/Co nanoparticles with decahedral and icosahedral shape, their characterization using Cs-corrected scanning transmission electron microscopy (STEM) and magnetic measurements using superconducting quantum interference device (SQUID) magnetometer. The Z-contrast imaging and energy dispersive X-ray spectroscopy (EDS) mapping showed an inhomogeneous alloying with minor segregation between Au and Co at nanoscale and the SQUID measurement exhibited the ferromagnetic behavior.

Evaluation of Surfactants on Thermo-Physical Properties of Magnesia-Oil Nanofluid

2018 ◽  
Vol 928 ◽  
pp. 106-112 ◽  
Author(s):  
Abdallah Yousef Mohammed Ali ◽  
Ahmed H. El-Shazly ◽  
M.F. Elkady ◽  
S.E. AbdElhafez
Keyword(s):  
Vinyl Pyrrolidone ◽  
Poly Vinyl Alcohol ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Mgo Nanoparticles ◽  
Transmission Electron ◽  
Wet Chemical ◽  
Cetyl Trimethyl Ammonium ◽  
Poly Vinyl Pyrrolidone ◽  
The Impact

The prime purpose of the current study was to investigate the consequence of surfactant on the kinematic viscosity, thermal conductivity, and stability of MgO-oil based nanofluid. Magnesia (MgO) nanoparticles were prepared by the wet chemical method. Structural and morphological analysis of synthesized nanoparticles were performed via X-ray diffraction (XRD) and Transmission electron microscope (TEM). Subsequently, nanofluid was prepared at a solid concentration of 0.025% in presence of various surfactants with the aid of ultrasonic technique. The impact of the different surfactants (Cetyl Trimethyl Ammonium Bromide (CTAB), Poly Vinyl Pyrrolidone (PVP), Poly Vinyl Alcohol (PVA), and Oleic Acid) on the nanofluid stability was tested. It was evident that CTAB and PVA surfactants establish the most stable prepared MgO-oil based nanofluid. The experiments revealed that the maximum UV–Vis absorbance of the solution corresponds to the dispersion of CTAB in the base fluid.

Origin of blue emission in ThO2 nanorods: exploring it as a host for photoluminescence of Eu3+, Tb3+ and Dy3+

RSC Advances ◽  
2014 ◽  
Vol 4 (93) ◽  
pp. 51244-51255 ◽  
Author(s):  
Santosh K. Gupta ◽  
P. S. Ghosh ◽  
A. Arya ◽  
V. Natarajan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Reverse Micelle ◽  
Cetyl Trimethyl Ammonium Bromide ◽  
Blue Emission ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Cetyl Trimethyl Ammonium

Nanorods of ThO2 were synthesized in a reverse micelle technique using cetyl trimethyl ammonium bromide as a surfactant and characterized by X-ray diffraction and transmission electron microscopy.

scholarly journals Preparation of Nano-Sized Mesoporous Silica and Its Application in Immobilization of β-galactosidase from Aspergillus Oryzae

2017 ◽  
Vol 9 (1) ◽  
pp. 65
Author(s):  
Jiao Yang ◽  
Zhenzhen Liu ◽  
Huan Ge ◽  
Sufang Sun
Keyword(s):  
Mesoporous Silica ◽  
Aspergillus Oryzae ◽  
Nitrogen Adsorption ◽  
Ammonium Bromide ◽  
Experimental Conditions ◽  
Transmission Electron ◽  
Alkaline Conditions ◽  
Activity Yield ◽  
Cetyl Trimethyl Ammonium ◽  
First Time

In alkaline conditions, monodisperse nano-sized mesoporous silica was synthesized using cetyl trimethyl ammonium bromide (CTAB) as template and tetraethoxysilane (TEOS) silica as source in ethanol / water cosolvent conditions. Using method of nitrogen adsorption, specific surface area of the dried monodisperse nano-sized mesoporous silica was about 1591 m2/g and the pore size was about 3.8 nm. The field-emission scanning electron microscope (SEM) micrographs showed that the silica particles obtained were spherical with an approximate diameter of 160 nm and of good dispersion. Transmission electron microscopy (TEM) revealed that the carrier had an excellent cellular structure with disordered multi-channels and smooth surface. The nano-sized mesoporous silica above was employed to immobilize β-galactosidase from aspergillus oryzae for the first time. At the experimental conditions in section 2.4, the enzyme activity and the activity yield were 535.11 U/g dry carrier and 79.63%, respectively. Kinetic data of the immobilized enzyme such as optimum temperature, pH, and thermal and pH stability among other valuable results were also determined.

Morphology Properties of Polyurethane/Clay Nanocomposites Base on Palm Oil Polyol Paint

2013 ◽  
Vol 647 ◽  
pp. 701-704 ◽  
Author(s):  
Rihayat Teuku ◽  
Amroel Suryani
Keyword(s):  
Palm Oil ◽  
Thermoplastic Polyurethane ◽  
Ammonium Bromide ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Organically Modified ◽  
Cetyl Trimethyl Ammonium ◽  
Clay Layers ◽  
Clay Aggregates

An organically modified clay and a pristine clay were used to prepare biodegradable thermoplastic polyurethane (PU) paint/clay nanocomposites. In this paper, polyurethane paint /clay nanocomposites base on palm oil polyol were prepared by isocyanate, polyol and organoclay (a clay modified with Cetyl trimethyl ammonium Bromide (CTAB) and Octadecylamines (ODA). The morphologies of samples were revealed by transmission electron microscopy (TEM) and Intercalation of PU into clay galleries and crystalline structure of PU were investigated using X-ray diffraction (XRD). The morphology of the resulting composite showed a combination of intercalated and partially exfoliated clay layers with occasional clay aggregates

scholarly journals Solvent-Free Mechanochemical Synthesis and Characterization of Nickel Tellurides with Various Stoichiometries: NiTe, NiTe2 and Ni2Te3

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1959
Author(s):  
Matjaž Kristl ◽  
Sašo Gyergyek ◽  
Srečo D. Škapin ◽  
Janja Kristl
Keyword(s):  
Electron Microscopy ◽  
Magnetic Measurements ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
X Ray ◽  
Transmission Electron ◽  
Energy Consuming ◽  
Tga And Dsc

The paper reports the synthesis of nickel tellurides via a mechanochemical method from elemental precursors. NiTe, NiTe2, and Ni2Te3 were prepared by milling in stainless steel vials under nitrogen, using milling times from 1 h to 12 h. The products were characterized by powder X-ray diffraction (pXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), UV-VIS spectrometry, and thermal analysis (TGA and DSC). The products were obtained in the form of aggregates, several hundreds of nanometers in size, consisting of smaller nanosized crystallites. The magnetic measurements revealed a ferromagnetic behavior at room temperature. The band gap energies calculated using Tauc plots for NiTe, NiTe2, and Ni2Te3 were 3.59, 3.94, and 3.70 eV, respectively. The mechanochemical process has proved to be a simple and successful method for the preparation of binary nickel tellurides, avoiding the use of solvents, toxic precursors, and energy-consuming reaction conditions.

scholarly journals Morphology-Controlled Synthesis Of SrTiO3 Nanocube By Capping Agent-Assisted Solvothermal Method

Molekul ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Yulia Eka Putri ◽  
Alvionita Alvionita ◽  
Rini Rahma Yanti ◽  
Diana Vanda Wellia
Keyword(s):  
Cetyl Trimethyl Ammonium Bromide ◽  
Molar Ratio ◽  
Head Group ◽  
Ammonium Bromide ◽  
Capping Agent ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Transmission Electron ◽  
Cetyl Trimethyl Ammonium

The synthesis of SrTiO3 nanocubes have been carried out by solvothermal process using cetyl trimethyl ammonium bromide (CTAB) as capping agent to control the particles morphology. The condition of the synthesis was obtained at 160 ºC for 24 hours with molar ratio of SrTiO3 and capping agent was 1 : 1. The X-ray diffraction (XRD) pattern shows that SrTiO3 adopts a perovskite structure with a higher intensity of 110 at 2q:32.33º and the crystallite size calculated from FWHM was found to be 41 nm. Fourier transform infrared (FTIR) spectrum shows a shift in particular absorption band attributed the interaction between SrTiO3 particles surface and the head group of CTAB molecules. Transmission electron microscopy (TEM) image shows the cubic-like particles of SrTiO3, this indicatesthat CTAB successfully functions as capping agent on the synthesis of SrTiO3.

Magnetic Properties of Co Nanoparticles in an AlMCM41 Mesoporous Host

2001 ◽  
Vol 676 ◽  
Author(s):  
Jin-Seung Jung ◽  
Jun-Yong Kim ◽  
Weon-Sik Chae ◽  
Yong-Rok Kim ◽  
Jong-Ho Jun ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Volume Fraction ◽  
Magnetic Measurements ◽  
X Ray Diffraction ◽  
Host Matrix ◽  
Transmission Electron ◽  
Small Volume Fraction ◽  
Size Of Particles ◽  
Co Nanoparticles

ABSTRACTUltrafine cobalt particles in AlMCM41 silica tubes have been synthesized by ion exchange and the reduction with sodium borohydride. The role of this stable host matrix of AlMCM41 silica is to prevent agglomeration of the magnetic particles attached to the walls of AlMCM41 silica pores. The size of the host pores naturally limits the particle dimensions and thus improves their size distribution. Both magnetic susceptibility measurements and transmission electron microscopy (TEM) show a narrow distribution size of the nanoparticles. Well controlled insertion of the magnetic material to the host channel excludes formation of bulk particles outside the host material grains, which was confirmed by the TEM studies. X-ray diffraction data did not show peaks corresponding to a crystalline cobalt, but this maybe due to small size of particles and their relatively small volume fraction. The content of Co in the AlMCM41 host was measured using both magnetic measurements and elemental analysis.

Ferromagnetic Behaviour in Nanoscale Cobalt Particles Dispersed by Zeolite Na-X.

1995 ◽  
Vol 384 ◽  
Author(s):  
I. Hussain ◽  
I. Gameson ◽  
P.A. Anderson ◽  
P. P. Edwards
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Magnetic Measurements ◽  
Hydrogen Atmosphere ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Simple Solid State Reaction

ABSTRACTThis investigation has looked at the preparation of nanoscale cobalt particles by a simple solid state reaction involving cobalt (II) nitrate and zeolite Na-X under vacuum conditions followed by reduction in an hydrogen atmosphere. Samples were characterised by powder x-ray diffraction and scanning/transmission electron microscopy (TEM). Magnetic measurements were performed on the samples below 300 K using a SQUID magnetometer.

scholarly journals Dissimilatory Iron-Reducing Microorganisms Are Present and Active in the Sediments of the Doce River and Tributaries Impacted by Iron Mine Tailings from the Collapsed Fundão Dam (Mariana, MG, Brazil)

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 244
Author(s):  
Carolina N. Keim ◽  
Jilder D. P. Serna ◽  
Daniel Acosta-Avalos ◽  
Reiner Neumann ◽  
Alex S. Silva ◽  
...  
Keyword(s):  
Bottom Sediments ◽  
Magnetic Measurements ◽  
Culture Media ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ferric Oxyhydroxide ◽  
Transmission Electron ◽  
Iron Mine ◽  
Organic Matter Oxidation ◽  
Doce River

On 5 November 2015, a large tailing deposit failed in Brazil, releasing an estimated 32.6 to 62 million m3 of iron mining tailings into the environment. Tailings from the Fundão Dam flowed down through the Gualaxo do Norte and Carmo riverbeds and floodplains and reached the Doce River. Since then, bottom sediments have become enriched in Fe(III) oxyhydroxides. Dissimilatory iron-reducing microorganisms (DIRMs) are anaerobes able to couple organic matter oxidation to Fe(III) reduction, producing CO2 and Fe(II), which can precipitate as magnetite (FeO·Fe2O3) and other Fe(II) minerals. In this work, we investigated the presence of DIRMs in affected and non-affected bottom sediments of the Gualaxo do Norte and Doce Rivers. The increase in Fe(II) concentrations in culture media over time indicated the presence of Fe(III)-reducing microorganisms in all sediments tested, which could reduce Fe(III) from both tailings and amorphous ferric oxyhydroxide. Half of our enrichment cultures converted amorphous Fe(III) oxyhydroxide into magnetite, which was characterized by X-ray diffraction, transmission electron microscopy, and magnetic measurements. The conversion of solid Fe(III) phases to soluble Fe(II) and/or magnetite is characteristic of DIRM cultures. The presence of DIRMs in the sediments of the Doce River and tributaries points to the possibility of reductive dissolution of goethite (α-FeOOH) and/or hematite (α-Fe2O3) from sediments, along with the consumption of organics, release of trace elements, and impairment of water quality.

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