Synthesis and Activity of Co-doped Barium Cerium Zirconate for Hydrogen Reforming and Purification

2008 ◽  
Vol 1126 ◽  
Author(s):  
Aravind Suresh ◽  
Joysurya Basu ◽  
Nigel M Sammes ◽  
Barry C Carter ◽  
Benjamin A Wilhite
Keyword(s):  
Hydrogen Generation ◽  
Ac Impedance ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Ac Impedance Spectroscopy ◽  
Methanol Partial Oxidation ◽  
Transmission Electron ◽  
Catalytically Active ◽  
Different Temperatures ◽  
Co Precipitation

AbstractBaCe0.25Zr0.60Co0.15O3-x (BCZC) was synthesized via oxalate co-precipitation route. Material was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Catalytic activity of BCZC with respect to hydrogen generation via methanol partial oxidation was determined. Conductivity of the material at different temperatures and under different environments was determined by AC impedance spectroscopy. XRD and TEM results indicated that BCZC was synthesized as a homogeneous cubic phase material. Catalyst tests indicated that BCZC was catalytically active towards hydrogen generation and AC impedance results were positive enough to warrant further electrochemical studies.

The Features of a High-Temperature Synthesis of ZrO2 in a Core-Shell ZrO2@C Structure

2019 ◽  
Vol 950 ◽  
pp. 133-137
Author(s):  
Alexander M. Volodin ◽  
Vladimir O. Stoyanovskii ◽  
Vladimir I. Zaykovskii ◽  
Roman M. Kenzhin ◽  
Aleksey A. Vedyagin
Keyword(s):  
Elevated Temperatures ◽  
Cubic Phase ◽  
Core Shell ◽  
X Ray Diffraction ◽  
High Temperature Synthesis ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Carbon Coated ◽  
Physicochemical Methods ◽  
Argon Adsorption

Zirconium oxide was obtained via traditional precipitation from a ZrOCl2 solution with ammonia followed by drying at 110 °C. The carbon-coated samples were synthesized by calcination of the pristine zirconia mixed with polyvinylalcohol. The obtained ZrO2@C samples of core-shell structure as well as the reference samples of pristine zirconia were calcined at different temperatures from 500 to 1400 °C. All the materials were examined by a set of physicochemical methods (a low-temperature argon adsorption, transmission electron microscopy, X-ray diffraction analysis, photoluminescence spectroscopy). It was found that the carbon coating prevents the sintering of the oxide nanoparticles, which allows one to maintain the specific surface area, the size of the oxide core and, finally, stabilize its phase composition. Transformation of the cubic phase into monoclinic phase becomes significantly complicated. Thus, 40% of the cubic phase was detected even after calcination of the ZrO2@C sample at 1400 °C. Moreover, the carbon-coated samples treated at elevated temperatures with subsequent removal of the carbon shell were found to possess the highest concentration of the defects related to a presence of the anion vacancies in zirconia.

scholarly journals Synthesis and Characterization of Cysteine-Capped CdSe Nanoparticles Using an Alternative of Selenium

2019 ◽  
Vol 31 (11) ◽  
pp. 2457-2460
Author(s):  
K.E. Mokubung ◽  
M.J. Moloto ◽  
K.P. Mubiayi ◽  
N. Moloto
Keyword(s):  
Cdse Nanoparticles ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Visible Absorption ◽  
Prepared Nanoparticles ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Xrd Patterns ◽  
Average Size

Present work reports synthesis of L-cysteine capped CdSe nanoparticles at different temperatures via an aqueous medium, non-toxic and green colloidal route. Cadmium chloride (CdCl2·5H2O) and sodium selenite (Na2SeO3) were used as cadmium and selenium sources respectively. The prepared nanoparticles are characterized by UV-visible absorption and photoluminescence spectroscopy, Fourier transform infrared, X-ray diffraction and transmission electron microscopy. The XRD patterns confirm a cubic phase structure of the prepared nanoparticles at 55, 75 and 95 ºC, respectively. The TEM analysis, optical absorption and photoluminescence spectra shows epitaxial growth of CdSe nanoparticles as the temperature increases with average size diameter of 4.12 ± 0.32, 5.02 ± 0.234 and 5.53 ± 0.321 nm for 55, 75 and 95 ºC, respectively.

Fabrication and Up-Conversion Luminescence of Er3+:Y2O3 Nanoparticles

2008 ◽  
Vol 8 (3) ◽  
pp. 1211-1213 ◽  
Author(s):  
Luo Jun-Ming ◽  
Li Yong-Xiu ◽  
Deng Li-Ping ◽  
Yuan Yong-Rui ◽  
Chen Wei-Fan
Keyword(s):  
Doping Concentration ◽  
Green Emission ◽  
Average Diameter ◽  
Precipitation Method ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Radiative Transitions ◽  
Transmission Electron ◽  
Co Precipitation

Y2O3 nanoparticles doped with different concentrations of Er3+ were prepared by the co-precipitation method. X-ray diffraction and transmission electron microscopy results show that Er3+ dissolves completely in the Y2O3 cubic phase. The Er3+:Y2O3 nanoparticles are homogeneous in size and nearly spherical, and the average diameter of the particles after being calcined at 1,000 °C for 2 h is in the range of 40–60 nm. When Er3+:Y2O3 nanoparticles are excited under a 980 nm diode laser, there are two main emission bands: green emission centered at 562 nm corresponding to the 4S3/2/2H11/2 → 4I15/2 radiative transitions and red emission centered at 660 nm corresponding to the 4F9/2 ∼ 4I15/2 radiative transitions. By changing the doping concentration of Er3+ ions, the up-conversion luminescence can be gradually tuned from green to red.

scholarly journals Zinc Titanate Nanopowders. Synthesis and Characterization

2021 ◽  
Author(s):  
M Gabal ◽  
Y.M. Al Angari
Keyword(s):  
Nitrogen Adsorption ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Zinc Titanate ◽  
Low Dielectric ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Precursor Decomposition ◽  
Co Precipitation ◽  
Adsorption Desorption

Abstract Zinc titanates nanopowders viz.; Zn2TiO4, ZnTi3O8 and ZnTiO3 were synthesized through the thermal decomposition course of ZnC2O4.2H2O-TiO2 precursor (1:1 mole ratio), prepared via a new co-precipitation method up to 900oC. Thermogravimetric measurement (TG) was utilized to characterize the precursor decomposition while X-ray diffraction (XRD), Fourier transform infra-red (FT-IR) were used to characterize the decomposition products as well as the phase transitions at different temperatures. XRD revealed the starting of titanates formation at 700oC via detecting Zn2TiO4 along with ZnO and TiO2 (anatase) diffraction peaks. By increasing the calcination temperature to 800oC, the ZnO content vanished with the appearing of Zn2Ti3O8 besides ZnTi2O4 and impurities of TiO2 (anatase). Finally at 900oC, the Zn2Ti3O8 content was decomposed into ZnTiO3. Nitrogen adsorption-desorption isotherm of the calcined precursor at 900oC indicated low specific surface area of 7.1 m2 g-1 in accordance with the agglomeration nature estimated via transmission electron microscopy (TEM) study. The conductivity measurements showed semiconducting behavior of the prepared titanates with ferroelectric transition in the range 200-308oC.The obtained low dielectric value suggests the uses of present titanates as a co-fired ceramic or resonator ceramics.

Characterization of Al2(WO4)3 Synthesized by Co-Precipitation Method

2014 ◽  
Vol 798-799 ◽  
pp. 85-89 ◽  
Author(s):  
E.S.G. Junior ◽  
P.M . Jardim
Keyword(s):  
Precipitation Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Co Precipitation ◽  
Alpha Alumina

Al2(WO4)3was synthesized by co-precipitation using Na2WO4and Al (NO3)3as precursors. After drying the precipitate, it was calcined at different temperatures between 500°C and 800°C. The crystallization and degradation temperatures of the samples were evaluated by means of Differential Scanning Calorimetry (DSC), Thermogravimetry (TG) and X-Ray Diffraction (XRD). It was observed that the crystallization starts at around 600°C, however Transmission Electron Microscopy (TEM) analysis showed that at this temperature the sample is partially amorphous. The degradation of the material starts at around 1200°C and at 1400°C the tungsten oxide has almost completely evaporated and the material is transformed mainly in alpha-alumina.

Experimental Study of Property of Magnetic Nanoparticle Prepared in Different Temperatures

2011 ◽  
Vol 412 ◽  
pp. 155-158
Author(s):  
Fan Wang ◽  
De Cai Li ◽  
Meng Zhang ◽  
Zhi Li Zhang
Keyword(s):  
Saturation Magnetization ◽  
Magnetic Nanoparticle ◽  
X Ray Diffraction ◽  
Magnetic Liquid ◽  
X Ray ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Magnetic Liquids ◽  
Different Temperatures ◽  
Co Precipitation

For prepare magnetic liquids with good property, the authors prepared Magnetic Fe3O4 nanoparticles by co-precipitation in different temperatures including 60°C, 70°C, 80°C in this experiment and analyzed the product of Magnetic Fe3O4 nanoparticles by X-ray Diffraction Analysis, Transmission Electron Scanning, Saturation Magnetization Test and the result indicate that Magnetic Fe3O4 nanoparticles prepared at 70°C have good crystallinity and high saturation magnetization and suitable for prepare magnetic liquid.

scholarly journals Morphologic, structural, and magnetic characterization of cobalt ferrite nanoparticles synthesized at different temperatures

2021 ◽  
Vol 9 (9) ◽  
pp. 399-405
Author(s):  
Kétlin Santos Alberton ◽  
Liza Bruna Reis Monteiro ◽  
Anne Beatriz Ramos Moraes ◽  
Raynara Vitória dos Santos Paiva Bucar ◽  
Maicon Maciel Ferreira de Araujo ◽  
...  
Keyword(s):  
Cobalt Ferrite ◽  
Magnetic Moments ◽  
X Ray Diffraction ◽  
Cofe2o4 Nanoparticles ◽  
First Order ◽  
Transmission Electron ◽  
Two Samples ◽  
Different Temperatures ◽  
Co Precipitation

In this study we report on the synthesis and characterization of cobalt ferrite (CoFe2O4) nanoparticles (NPs), synthesized by chemical co-precipitation in alkaline medium. Two samples were synthesized at two different temperatures, 35 and 90 oC. Both samples were characterized by Transmission Electron Microscopy (TEM), x-ray diffraction (XRD), and room-temperature (RT) magnetization. Two samples showed superparamagnetic behavior (SPM) at RT. TEM reveals morphological mean diameter increasing 5.8 nm to 10.4 nm, with the increase of the co-precipitation temperature. XRD confirm the inverse cubic spinel structure. The RT magnetization curves were analyzed by the first-order Langevin function averaged out by a lognormal distribution function of magnetic moments. This analysis showed saturation magnetization and magnetic moment increases from 60.2 to 74.8 emu/g and from 3.9 x 103 to 8.2 x 103 mB, respectively.

Magnetic and dielectric properties of BiFeO3 nanoparticles

2015 ◽  
Vol 7 (2) ◽  
pp. 1393-1403
Author(s):  
Dr R.P VIJAYALAKSHMI ◽  
N. Manjula ◽  
S. Ramu ◽  
Amaranatha Reddy
Keyword(s):  
Diffuse Reflectance Spectrum ◽  
Precipitation Method ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Bifeo3 Nanoparticles ◽  
Transmission Electron ◽  
Multiferroic Bifeo3 ◽  
Pure Phase ◽  
Simple Chemical ◽  
Co Precipitation

Single crystalline nano-sized multiferroic BiFeO3 (BFO) powders were synthesized through simple chemical co-precipitation method using polyethylene glycol (PEG) as capping agent. We obtained pure phase BiFeO3 powder by controlling pHand calcination temperature. From X-ray diffraction studies the nanoparticles were unambiguously identified to have a rhombohedrally distorted perovskite structure belonging to the space group of R3c. No secondary phases were detected. It indicates single phase structure. EDX spectra indicated the appearance of three elements Bi, Fe, O in 1:1:3. From the UV-Vis diffuse reflectance spectrum, the absorption cut-off wavelength of the BFO sample is around 558nm corresponding to the energy band gap of 2.2 eV. The size (60-70 nm) and morphology of the nanoparticles have been analyzed using transmission electron microscopy (TEM).   Linear M−H behaviour and slight hysteresis at lower magnetic field is observed for BiFeO3 nanoparticles from Vibrating sample magnetometer studies. It indicates weak ferromagnetic behaviour at room temperature. From dielectric studies, the conductivity value is calculated from the relation s = L/RbA Sm-1 and it is around 7.2 x 10-9 S/m.

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

Microstructure Characterization of Metal Mixed Oxides

MRS Advances ◽  
2017 ◽  
Vol 2 (64) ◽  
pp. 4025-4030 ◽  
Author(s):  
T. Kryshtab ◽  
H. A. Calderon ◽  
A. Kryvko
Keyword(s):  
Mixed Oxides ◽  
Profile Analysis ◽  
Atomic Resolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Reconstruction Procedure ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Co Precipitation

ABSTRACTThe microstructure of Ni-Mg-Al mixed oxides obtained by thermal decomposition of hydrotalcite-like compounds synthesized by a co-precipitation method has been studied by using X-ray diffraction (XRD) and atomic resolution transmission electron microscopy (TEM). XRD patterns revealed the formation of NixMg1-xO (x=0÷1), α-Al2O3 and traces of MgAl2O4 and NiAl2O4 phases. The peaks profile analysis indicated a small grain size, microdeformations and partial overlapping of peaks due to phases with different, but similar interplanar spacings. The microdeformations point out the presence of dislocations and the peaks shift associated with the presence of excess vacancies. The use of atomic resolution TEM made it possible to identify the phases, directly observe dislocations and demonstrate the vacancies excess. Atomic resolution TEM is achieved by applying an Exit Wave Reconstruction procedure with 40 low dose images taken at different defocus. The current results suggest that vacancies of metals are predominant in MgO (NiO) crystals and that vacancies of Oxygen are predominant in Al2O3 crystals.

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