Sintering of Nanocrystalline CeO2 Ceramics

Kleinlogel, C.; Gauckler, Ludwig J.

doi:10.1002/1521-4095(200107)13:14<1081::aid-adma1081>3.0.co;2-d

Cited by 186 publications

(108 citation statements)

References 14 publications

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“…6a) reveals the Ce and Co peaks, indicating the co-deposition of cerium and cobalt. If we consider that the addition of small amount of cobalt oxide to gadolinia-stabilized ceria resulted in much lower sintering temperature, higher shrinkage rates and grain sizes in the final sintered product [51][52][53][54], these preliminary results appear promising for SOFC electrolyte applications.…”

Section: Resultsmentioning

confidence: 99%

From ceria nanotubes to nanowires through electrogeneration of base

2009

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The preparation of Ce(OH) 3 /CeO 2 nanostructures (NSs) through electrogeneration of base into anodic alumina membranes was studied. The effects of solvent (alcohol and/or water), Ce 3? partner anion nature (chloride or nitrate) and concentration, applied potential or current density in driving the morphology toward nanowires (NWs) and/or nanotubes (NTs) was described. The structural analysis performed by X-Ray Diffraction and Raman Spectroscopy allowed to evidence that the presence of Ce(IV) into the nanostructures strongly depends on the oxygen content in the growing environment.

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Section: Resultsmentioning

confidence: 99%

From ceria nanotubes to nanowires through electrogeneration of base

2009

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“…However, the need to produce such cells economically at low temperature remains an issue and has prompted studies into the use of dopants and nano-sized powders to reduce the 1200C traditionally required to densify CGO electrolytes [4,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”

Section: Objectives and Experimentsmentioning

confidence: 99%

Low Temperature Constrained Sintering of Cerium Gadolinium OxideFilms for Solid Oxide Fuel Cell Applications

Nicholas

2007

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Cerium gadolinium oxide (CGO) has been identified as an acceptable solid oxide fuel cell (SOFC) electrolyte at temperatures (500-700°C) where cheap, rigid, stainless steel interconnect substrates can be used. Unfortunately, both the high sintering temperature of pure CGO, >1200°C, and the fact that constraint during sintering often results in cracked, low density ceramic films, have complicated development of metal supported CGO SOFCs.The aim of this work was to find new sintering aids for Ce 0.9 Gd 0.1 O 1.95 , and to evaluate whether they could be used to produce dense, constrained Ce 0.9 Gd 0.1 O 1.95 films at temperatures below 1000°C. To find the optimal sintering aid, Ce 0.9 Gd 0.1 O 1.95 was doped with a variety of elements, of which lithium was found to be the most effective.Dilatometric studies indicated that by doping CGO with 3mol% lithium nitrate, it was possible to sinter pellets to a relative density of 98.5% at 800C-a full one hundred degrees below the previous low temperature sintering record for CGO. Further, it was also 2 found that a sintering aid's effectiveness could be explained in terms of its size, charge and high temperature mobility.A closer examination of lithium doped Ce 0.9 Gd 0.1 O 1.95 indicated that lithium affects sintering by producing a Li 2 O-Gd 2 O 3 -CeO 2 liquid at the CGO grain boundaries. Due to this liquid phase sintering, it was possible to produce dense, crack-free constrained films of CGO at the record low temperature of 950C using cheap, colloidal spray deposition processes. This is the first time dense constrained CGO films have been produced below 1000C and could help commercialise metal supported ceria based solid oxide fuel cells. Thesis Motivation, Background and Overview MotivationMore efficient technologies are needed if the world is to meet the doubling of energy demand that is projected to occur in the next 25 years. Given the large natural reserves of hydrocarbons and the existing infrastructure, it seems likely that traditional fuels (such as gasoline and liquefied natural gas) will retain their importance, even as alternatives such as bio-fuels enter the marketplace. Thankfully, the efficiency increases possible by electrochemically reacting these fuels inside a fuel cell instead of combusting them are considerable, making it possible to lower the environmental costs associated with their continued use. For instance, solid oxide fuel cells (SOFCs) are expected to achieve first law efficiencies of 80-85% when used with cogeneration [1]; whereas, the mostefficient combustion systems used today only achieve efficiencies of 50% [2]. Fuel Cell BasicsA fuel cell utilizing an oxygen-conducting electrolyte, such as a solid oxide fuel cell, is schematically illustrated in Figure 1. Here an oxidant (usually atmospheric O 2 ) is added to the cathode chamber of the fuel cell where it takes on electrons and destroys oxygen ion vacancies within the electrolyte by filling them with oxygen. At the same time, fuel, such as H 2 , is added to the anode chamber where i...

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“…Nano-sized CeO 2 is used in many applications like cosmetic materials, high-storage capacitor devices, 16 buffer layers for conductors, [17][18][19] fuel cells, 20,21 and optical devices.…”

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confidence: 91%

Structural and Spectroscopic Investigation of Ceria Nanofibers Fabricated by Electrospinning Process

Hwang¹,

Park²,

Kang³

2011

Bulletin of the Korean Chemical Society

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We fabricated ceria (CeO 2 ) nanofibers by applying a mixed solution of polyvinylpyrrolidone (PVP) and various concentrations of cerium nitrate hydrate (Ce(NO 3 ) 3 ) ranging from 15.0 to 26.0 wt % by the electrospinning process. Ceria nanofibers were obtained after calcining PVP/Ce(NO 3 ) 3 nanofiber composites at 873 and 1173 K. The SEM images indicated that the diameters of CeO 2 nanofibers calcined at 873 and 1173 K were smaller than those of nanofibers obtained at RT. As the amount of cerium increased, the diameter of CeO 2 nanofibers increased. XRD analysis revealed that the ceria nanofibers were in cubic form. TEM results revealed that the ceria nanofibers were formed by the interconnection of Ce oxide nanoparticles. The ceria nanofibers obtained at low concentrations of Ce (CeL) showed spotty ring patterns indicated that the ceria nanofibers were polycrystalline structure. And the ceria nanofibers obtained at high concentration of Ce (CeH) showed fcc (001) diffraction pattern. XPS study indicated that the oxidation of Ce shifted from Ce 3+ to Ce 4+ as the calcination temperature increased.

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Sintering of Nanocrystalline CeO2 Ceramics

Cited by 186 publications

References 14 publications

From ceria nanotubes to nanowires through electrogeneration of base

From ceria nanotubes to nanowires through electrogeneration of base

Low Temperature Constrained Sintering of Cerium Gadolinium OxideFilms for Solid Oxide Fuel Cell Applications

Structural and Spectroscopic Investigation of Ceria Nanofibers Fabricated by Electrospinning Process

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