Effect of sintering aid (CoO) on transport properties of nanocrystalline Gd doped ceria (GDC) materials prepared by co-precipitation method

2013 ◽  
Vol 575 ◽  
pp. 455-460 ◽  
Author(s):  
Ashok Kumar Baral ◽  
Hari Prasad Dasari ◽  
Byung-Kook Kim ◽  
Jong-Ho Lee
Keyword(s):  
Transport Properties ◽  
Precipitation Method ◽  
Doped Ceria ◽  
Sintering Aid ◽  
Co Precipitation

Preparation and Characterization of Nanocomposite Calcium Doped Ceria Electrolyte With Alkali Carbonates (NK-CDC) for SOFC

2010 ◽  
Author(s):  
Ghazanfar Abbas ◽  
Rizwan Raza ◽  
Muhammad Ashraf Chaudhry ◽  
Bin Zhu
Keyword(s):  
Electron Microscopy ◽  
Fossil Fuels ◽  
Electrochemical Impedance ◽  
Renewable Energy Sources ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Doped Ceria ◽  
Alternative Source ◽  
Calcium Doped ◽  
Co Precipitation

The entire world’s challenge is to find out the renewable energy sources due to rapid depletion of fossil fuels because of their high consumption. Solid Oxide Fuel Cells (SOFCs) are believed to be the best alternative source which converts chemical energy into electricity without combustion. Nanostructured study is required to develop highly ionic conductive electrolyte for SOFCs. In this work, the calcium doped ceria (Ce0.8Ca0.2O1.9) coated with 20% molar ratio of two alkali carbonates (CDC-M: MCO3, where M = Na and K) electrolyte was prepared by co-precipitation method in this study. Ni based electrode was used to fabricate the cell by dry pressing technique. The crystal structure and surface morphology was characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). The particle size was calculated in the range of 10–20nm by Scherrer’s formula and compared with SEM and TEM results. The ionic conductivity was measured by using AC Electrochemical Impedance Spectroscopy (EIS) method. The activation energy was also evaluated. The performance of the cell was measured 0.567W/cm2 at temperature 550°C with hydrogen as a fuel.

Superior sinterability of nano-crystalline gadolinium doped ceria powders synthesized by co-precipitation method

2010 ◽  
Vol 495 (1) ◽  
pp. 238-241 ◽  
Author(s):  
D. Hari Prasad ◽  
H.-R. Kim ◽  
J.-S. Park ◽  
J.-W. Son ◽  
B.-K. Kim ◽  
...  
Keyword(s):  
Precipitation Method ◽  
Doped Ceria ◽  
Nano Crystalline ◽  
Co Precipitation ◽  
Gadolinium Doped Ceria

Study of Structural and Electrical Transport Properties of Polycrystalline La1-XCaXMnO3 (x=0.33, 0.5 and 0.9) Prepared by a Co-Precipitation Method

2013 ◽  
Vol 652-654 ◽  
pp. 576-580 ◽  
Author(s):  
Mya Theingi ◽  
Ji Ma ◽  
Hui Zhang ◽  
Xiang Gao ◽  
Jian Hong Yi ◽  
...  
Keyword(s):  
Transport Properties ◽  
Electrical Transport ◽  
Perovskite Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Electrical Transport Properties ◽  
X Ray ◽  
Manganite Perovskite ◽  
Polycrystalline Ceramics ◽  
Co Precipitation

Manganite perovskite La1-xCaxMnO3(x=0.33, 0.5 and 0.9) have been prepared by chemical co-precipitation method. Ammonium carbonate was used to coprecipitate lanthanum, calcium and manganese ions as carbonates under basic condition. This precursor on calcining at 900°C yields La-Ca-Mn-O perovskite phase. Follow by sintering at 1200°C after the powders were pressed into pellets gave La1-xCaxMnO3(LCMO) polycrystalline ceramics. The crystal phases of the resulting powders and ceramics were examined by X-ray diffraction (XRD) technique. The morphology of the powders was observed by scanning electron microscopy (SEM) and electrical transport properties of ceramics were measured by conventional four-point probe technique.

Effect of Doping Concentration on Grain Boundary Conductivity of Samaria Doped Ceria Composites

2021 ◽  
Author(s):  
Prerna Vinchhi ◽  
Roma Patel ◽  
Indrajit Mukhopadhyay ◽  
Abhijit Ray ◽  
Ranjan Pati
Keyword(s):  
Ionic Conductivity ◽  
Grain Boundary ◽  
Doping Concentration ◽  
Single Phase ◽  
Precipitation Method ◽  
Molecular Water ◽  
Doped Ceria ◽  
Boundary Conductivity ◽  
Co Precipitation ◽  
Hydrated Oxide

Abstract This work aims to study the effect of Sm3+ doping concentration on the grain boundary ionic conductivity of ceria. The materials were prepared by a modified co-precipitation method, where molecular water associated with the precursor has been utilized to facilitate the hydroxylation process. The synthesized hydroxide / hydrated oxide materials were calcined and the green body (pellet) has been sintered at high temperature in order to achieve highly dense (~ 96 %) pellet. The structural analyses were done using XRD and Raman spectroscopy, which confirm the single phase cubic structure of samaria doped ceria (SDC) nanoparticles and the surface morphology of sintered samples was studied using FESEM. The ionic conductivity was measured by AC impedance spectroscopy of the sintered pellets in the temperature range of 400-700 °C, which shows superior grain boundary conductivity. The grain boundary ionic conductivity of around 0.111 S/cm has been obtained for 15SDC composition at 600 °C.

STRUCTURAL AND OPTICAL PROPERTIES OF Eu3+ DOPED CERIUM OXIDE NANOPHOSPHORS

2011 ◽  
Vol 04 (01) ◽  
pp. 13-16 ◽  
Author(s):  
R. SRINIVASAN ◽  
A. CHANDRA BOSE
Keyword(s):  
Grain Size ◽  
Diffuse Reflectance Spectroscopy ◽  
Site Occupancy ◽  
Precipitation Method ◽  
Ceria Nanoparticles ◽  
Doped Ceria ◽  
Red Color ◽  
Average Grain Size ◽  
Co Precipitation ◽  
The Eu

Europium (3%) doped ceria nanoparticles were successfully prepared by 72 h hydrolysis assisted co-precipitation method. The average grain size of the as-prepared sample was 11 nm. The grain sizes were 12 and 18 nm for samples annealed at 500°C and 800°C respectively. The grain size effect on optical bandgap is investigated from diffuse reflectance spectroscopy (DRS). The orange and red color emissions of europium doped ceria nanoparticles were investigated by photoluminescence (PL) spectra under excitation of 330 nm. The high intense orange emission peak was found at 591 nm for as-prepared and annealed nanoparticles. This is the characteristic peak of the Eu 3+ ion corresponding to the parity allowed magnetic dipole transition between the 5 D 0–7 F 1 states. Site occupancy of europium ions was estimated by Red (R)/Orange (O) intensity ratio using PL spectrum.

Resistive Oxygen Gas Sensing Behavior of Zirconia-Doped Ceria

2011 ◽  
Vol 479 ◽  
pp. 143-148
Author(s):  
Kai Hsin Chang ◽  
Chin Lung Liu ◽  
Ya Ting Chan ◽  
Wen Cheieh Tsai ◽  
Chin Yi Chen
Keyword(s):  
Electrical Conductivity ◽  
Gas Sensing ◽  
Precipitation Method ◽  
Doped Ceria ◽  
Irregular Shapes ◽  
Nanocrystalline Ceria ◽  
Partial Pressures ◽  
Coating Morphology ◽  
Oxygen Gas ◽  
Co Precipitation

In the present study, nanocrystalline ceria powder and 10 mol% zirconia-doped ceria (10ZDC) powder were prepared by co-precipitation method from cerium nitrate and zirconium nitrate precursors. The resulting particles with irregular shapes were printed onto alumina substrate for the investigation of oxygen gas sensing behavior. The coating morphology of 10ZDC with a network structure revealed a better connection enhancing the sensing properties. Zirconia doping tended to inhibit the grain growth and decrease the lattice constant of ceria. Such effects may improve the electrical conductivity of 10ZDC under different oxygen partial pressures and shorten the response time of 10ZDC to the change of oxygen partial pressure.

Sintering of Transparent Polycrystal Nd:YAG with MgO as Additive

2008 ◽  
Vol 368-372 ◽  
pp. 426-428
Author(s):  
Yong Chao Li ◽  
Wang Guo ◽  
Tie Cheng Lu ◽  
Shi Hong Tong ◽  
Rui Xiao Fang ◽  
...  
Keyword(s):  
Grain Growth ◽  
Wavelength Region ◽  
Optical Transmittance ◽  
Precipitation Method ◽  
Vacuum Sintering ◽  
Sintering Aid ◽  
Optimal Weight ◽  
Weight Percentage ◽  
Pure Phase ◽  
Co Precipitation

In this paper, pure phase Nd-doped YAG powders were prepared by co-precipitation method with different amount of MgO (0~ 0.6 wt %) as additive. Transparent Nd:YAG ceramics were fabricated by vacuum sintering at 1750°C for 10 hours using the powders. Microstructure of the surfaces of thermally etched Nd:YAG ceramics was observed by SEM. Transmittance of the transparent Nd:YAG ceramics was measured over the wavelength region from 600nm to1200nm. The results showed that MgO as sintering aid can restrain abnormal grain growth and reduce pores in grains and at the same time, optical transmittance of the ceramics was increased. The optimal weight percentage of MgO added can be determined as 0.3wt % for the fabrication of transparent Nd:YAG ceramics.

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