Effect of Mg doping and sintering temperature on structural and morphological properties of samarium-doped ceria for IT-SOFC electrolyte

Ahmad, Syed Ismail; Mohammed, Tasneem; Bahafi, Amal; Suresh, M. Buchi

doi:10.1007/s13204-017-0567-x

Cited by 14 publications

(5 citation statements)

References 28 publications

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“…where n is the number of formula units in unit a cell, M is the sample's molecular weight, a is the lattice parameter and N A is the Avogadro's number [18]. The deviations in the crystallite size and lattice constant with varying concentrations of Zn in the samples are depicted in Figure 3.…”

Section: Xrd Analysismentioning

confidence: 99%

Structural, optical, room-temperature and low-temperature magnetic properties of Mg–Zn nanoferrite ceramics

Kumar

Ahmad

Lincoln

et al. 2019

Journal of Asian Ceramic Societies

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Mg-Zn nanocrystalline ferrites (Mg 1−x Zn x Fe 2 O 4 , where x = 0.0 to 1.0) were synthesized by the citrate gel auto-combustion route. XRD revealed the formation of nano-sized particles with cubic spinel structure. Lattice constant and specific surface area increased with Zn substitution. SEM micrographs revealed inhomogeneous grains with agglomerates; EDS spectra confirmed the stoichiometry. HRTEM images showed agglomerated nanoparticles with average particle sizes of 21 nm and 16 nm for x = 0.6 and 1.0, respectively, and lattice fringe images and SAED patterns showed nanocrystalline characteristics corroborating the XRD results. FTIR and Raman spectra recorded at room temperature confirmed the spinel structure of ferrites. VSM technique at room temperature used to measure magnetic properties. M S and H C were found to decrease with increases in the Zn concentration in Mg-Zn ferrites due to a weakening of the A-B interaction and decrease in the particle size and surface effect. Low-temperature magnetic studies were carried out in the ZFC and FC modes using SQUIDS by applying 100 Oe between temperatures of 5 and 400 K, and magnetic isotherms were recorded at temperatures of 51 and 310 K. The study revealed the superparamagnetic nature of the synthesized samples showing that the blocking temperature (T B ) depends on interparticle interactions.

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Section: Xrd Analysismentioning

confidence: 99%

Structural, optical, room-temperature and low-temperature magnetic properties of Mg–Zn nanoferrite ceramics

Kumar

Ahmad

Lincoln

et al. 2019

Journal of Asian Ceramic Societies

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“…BICUVOX.10 in the composite film act as the only matrix that is low concentration. This is why the absence of characteristic peaks of BICUVOX.10 in all components, which accord to previous reports [98,130,131]. The effect of applied potential was studied that varied potential range of -2.0 V to 2.0 V. Figure 5.22 was shown the reaction rate decease when applied negative potential.…”

Section: Characterization Of Bicuvox10/ysz Thin Filmsupporting

confidence: 86%

Non-faradaic electrochemical modification of catalytic activity (NEMCA) of propane oxidation on Pt/YSZ thin film cell

Lelalertsupakul

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In this work, non-Faradaic Electrochemical Modification of Catalytic Activity (NEMCA) of propane oxidation over Pt/yttria-stabilized zirconia (YSZ) thin films on alumina substrates has been studied. YSZ thin films were initially prepared by slurry dip coating and calcined at a relatively lower temperature of 800�oC. Propane oxidation at temperatures in a range of 300-500�oC clearly exhibited NEMCA. The maximum rate enhancement ratio was close to 3 at an applied potential of 1.0 V and a reaction temperature of 400�oC. The maximum faradaic efficiency was higher than 10,000 at an applied potential of 0.2 V and 300oC. However, NEMCA was not observed at 200 ?C. Nevertheless, the reproducibility of this cell was poor mainly because of weak adhesion between the YSZ film and the alumina substrate. This was caused by the low calcination temperature for the YSZ film. A higher temperature could not be used because the gold counter electrode had been found to diffuse into the alumina substrate at higher temperatures and lost its conductivity. For this reason, fabricated YSZ thin films adhered only weakly to alumina substrates and had a low-conductivity, highly porous structure. Copper doped bismuth vanadate (BICUVOX.10), which is a sintering aid, was added to the recipe for YSZ thin films to lower the films' sintering temperature. The BICUVOX.10 powder was prepared and characterized with XRD, XPS and DSC. The obtained XRD diffractogram and DSC curve confirmed the existence of a new phase transition. Composite films of YSZ and BICUVOX.10 were fabricated by screen printing and calcination 800 ?C. XRD analysis showed no solid-state reaction between YSZ and BICUVOX.10. Surface micrographs of thin film showed that increasing the BICUVOX.10 concentration resulted in a denser structure of the composite films. However, the addition of BICUVOX.10 decreased the open-circuit reaction rate due to the reduced surface areas of thin films. Nevertheless, increasing the concentration of BICUVOX.10 in thin films resulted in higher sensitivity of the reaction rate to the applied potential under anodic polarization region. The highest faradaic efficiency was obtained at 2.5 % BICUVOX.10.

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“…Ionic conducting oxides, especially ceria and its compounds, have acquired fame for the manufacture of solid oxide fuel cells, oxygen sensors and electrochemical applications. [1][2][3][4] Different dopants have been added to the ceria matrix according to the required applications in the past literature. The properties of ceria vary remarkably with different dopants and their concentrations.…”

Section: Introductionmentioning

confidence: 99%

Maxwell-Wagner Relaxation in Ca-, Sm- and Nd-doped Ceria

Ahmed¹,

Wang²,

Rehman³

et al. 2021

Eng. Sci.

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Doped ceria, i.e. Ce1-xMxO2-with M being dopant metal, has been a focus of great attention for solid oxide fuel cells (SOFCs) due to their high oxygen conduction. In the past literature, the dielectric relaxations in these materials have been ascribed to be caused by defect associates (MCeʺ-V̈) possessing different MCeʺ and V̈ distances. But we believe that with changing measurement and analysis techniques, it is necessary to invest our time to re-examine the already reported materials and take a detailed investigation of the underlying phenomenon behind their dielectric relaxations again. Thus, we have used solid-state reaction to prepare Ce1-xMxO2- with M=Ca, Sm, and Nd in x=0.1, 0.2, and 0.3 ratios, respectively. The as-prepared and post annealed samples were tested for dielectric properties from 300-1080 K with varying frequencies. The lowtemperature relaxation (R1) was argued to be a Maxwell-Wagner relaxation caused by humidity sensitivity. The hightemperature relaxation (R2) was ascribed to be caused by the hopping motion of oxygen vacancies. This fact was also supported by a detailed analysis of impedance spectra. While according to the previous reports, this relaxation is because of the oxygen-vacancy-dopant defect pair.

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Effect of Mg doping and sintering temperature on structural and morphological properties of samarium-doped ceria for IT-SOFC electrolyte

Cited by 14 publications

References 28 publications

Structural, optical, room-temperature and low-temperature magnetic properties of Mg–Zn nanoferrite ceramics

Structural, optical, room-temperature and low-temperature magnetic properties of Mg–Zn nanoferrite ceramics

Non-faradaic electrochemical modification of catalytic activity (NEMCA) of propane oxidation on Pt/YSZ thin film cell

Maxwell-Wagner Relaxation in Ca-, Sm- and Nd-doped Ceria

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