Influence of sintering additives of transition metals on the properties of gadolinium-doped barium cerate

Gorbova, E.; Maragou, V.; Medvedev, Dmitry; Demin, A.; Tsiakaras, Panagiotis

doi:10.1016/j.ssi.2008.02.065

Cited by 51 publications

(34 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…18,19 And yet, understanding hydration/protonation and oxidation processes at the atomic scale in cerates could help to improve and design new materials for electrolytes or electrodes in fuel cells. Moreover, Gd is known to be easily substituted to Ce in CeO 2 20 to provide oxygen vacancies and form an anionic conductor widely used as electrolyte in solid oxide fuel cells.…”

Section: ••mentioning

confidence: 99%

Thermodynamics of hydration and oxidation in the proton conductor Gd-doped barium cerate from density functional theory calculations

et al. 2012

View full text Add to dashboard Cite

Hydration and oxidation of gadolinium-doped barium cerate, a system with highly promising properties when used as electrolyte for protonic ceramic fuel cells, are investigated by means of density functional calculations. The energy landscape of oxygen vacancies and interstitial protons in this strongly distorted orthorhombic perovskite is computed. Although the most stable sites for protons are found in the close vicinity of the dopant, the picture of a very complex energy landscape emerges, in which some sites far away from Gd are found more stable than other ones in its close vicinity, due to the highly distorted geometry of the host materials. The fully hydrated phase can be approximated by a structure with 16 local minima. Both hydration (water incorporation) and oxidation (oxygen incorporation) are found to be exothermic processes with reaction enthalpies of −1.34 eV/H 2 O molecule and −0.70 eV/O atom, respectively. The hole polaron resulting from the exothermic incorporation of oxygen is found localized on oxygens around the dopant (small polaron) and carries a spin magnetic moment. Finally, the competition between hydration and oxidation is studied and discussed as a function of oxygen and water partial pressures.

show abstract

Section: ••mentioning

confidence: 99%

Thermodynamics of hydration and oxidation in the proton conductor Gd-doped barium cerate from density functional theory calculations

et al. 2012

View full text Add to dashboard Cite

show abstract

“…The proton reduction reaction to hydrogen is the rate-determining step in the hydrogen evolution reaction [43]. The slight amount of Ni doping in the BCZY phase enhances the electronic conductivity while maintaining the proton conductivity [31][32][33][34], which led to the enhancement of the current densities obtained using the Ni/BCZYN (x = 0.03) CLs. Moreover, in earlier papers, Ni dispersed on mixed conductors was found to lead to enhancement of the ERZ around the Ni catalyst particles with increasing electronic conductivity [24][25][26].…”

Section: Performances Of Ni/bczyn Clsmentioning

confidence: 99%

“…The CCL of µm-sized Ni-MPEC oxide cermet is formed on top of the CL to supply a highly electronically conductive layer, with high gas-diffusion rate from the separator (interconnect) to the CL, and an intimate contact between the separator and the CL. The slight amount of Ni doping in the proton-conducting oxide enhanced the electronic conductivity in the oxide [31][32][33][34], which was one of the most promising MPEC oxides for applications based on the above concept.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Evaluation of Ni Catalysts Supported on BaCe0.5Zr0.3−xY0.2NixO3−δ with Fused-Aggregate Network Structure for the Hydrogen Electrode of Solid Oxide Electrolysis Cell

et al. 2017

View full text Add to dashboard Cite

Nickel nanoparticles loaded on the electron-proton mixed conductor BaCe 0.5 Zr 0.3−x Y 0.2 Ni x O 3−δ (Ni/BCZYN, x = 0 and 0.03) were synthesized for use in the hydrogen electrode of a proton-conducting solid oxide electrolysis cell (SOEC). The Ni nanoparticles, synthesized by an impregnation method, were from 45.8 nm to 84.1 nm in diameter, and were highly dispersed on the BCZYN. The BCZYN nanoparticles, fabricated by the flame oxide synthesis method, constructed a unique microstructure, the so-called "fused-aggregate network structure". The BCZYN nanoparticles have capability of constructing a scaffold for the hydrogen electrode with both electronically conducting pathways and gas diffusion pathways. The catalytic activity on Ni/BCZYN (x = 0 and 0.03) catalyst layers (CLs) improved with the circumference length of the Ni nanoparticles. Moreover, the catalytic activity on the Ni/BCZYN (x = 0.03) CL was higher than that of the Ni/BCZYN (x = 0) CL. BCZYN (x = 0.03) possesses higher electronic conductivity than BCZYN (x = 0) due to the Ni doping, resulting in an enlarged effective reaction zone (ERZ). We conclude that the proton reduction reaction in the ERZ was the rate-determining step on the hydrogen electrode, and the reaction was enhanced by improving the electronic conductivity of the electron-proton mixed conductor BCZYN.

show abstract

“…Y-doped BaZrO 3 (BYZ), Gd-doped BaCeO 3 (BGC) and Sm-doped BaCeO 3 (BSC) were focused in this study, due to their high proton conductivities over the PCFC operating temperature range. [1][2][3][4][5][6][7][8][9][10][11] The major drawback for the utilization of these materials is their high sintering temperatures of above 1600 o C for doped BaZrO 3 1-6 and above 1450 o C for doped BaCeO 3 7-12 to achieve the relative densities of > 93% required for fuel cell applications. Several studies have pursued to lower the sintering temperatures of these materials.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies have pursued to lower the sintering temperatures of these materials. 9,12-17 Babilo and Haile 15 and Gorbova et al 9 studied the effect of NiO, CuO and ZnO as sintering aids on BYZ and BGC. Gorbova et al 9 achieved the relative density of 97, 92 and 94% with the addition of NiO, ZnO and CuO, respectively, in 10 at% BGC pellets (calcined at 1150 o C and sintered at 1450 o C).…”

Section: Introductionmentioning

confidence: 99%

Preparation of doped BaZrO3 and BaCeO3 from nanopowders

Pornprasertsuk

Yuwapattanawong

Permkittikul

et al. 2012

Int. J. Precis. Eng. Manuf.

View full text Add to dashboard Cite

To lower the calcining and sintering temperatures of 16 at% Y-doped BaZrO 3 (BYZ), Gd-doped BaCeO 3 (BGC) and Smdoped BaCeO 3 (BSC), nanopowders of BaCO 3 and either (i) yttria stabilized zirconia, (ii) Gd 2 O 3 and CeO 2 or (iii) Sm 2 O 3 and CeO 2 , were used as starting materials, respectively. BYZ powders were prepared by two mixing methods (i.e. ball milling and magnetic stirring), followed by calcination at 1050-1250 o C, while BSC and BGC powders were prepared by ball milling and calcined at 1050 o C. The results reveal that the ball milling and magnetic stirring methods yield similar results for BYZ powder preparation. By adding 1 wt% ZnO nanopowder, the average relative densities of BYZ pellets were increased from ∼70% to ∼96% at the sintering temperatures of 1300 o C. Thus, with the utilization of nanopowders and ZnO as a sintering aid, the calcining and sintering temperatures were lowered to 1050 o C and 1300 o C, respectively, while still attaining the relative bulk densities of both BYZ and BGC higher than 95.7%. However, since the relative bulk density of BSC reached only 93% even sintered at 1400 o C, ZnO was not an effective sintering aid for the BSC fabrication.

show abstract

Influence of sintering additives of transition metals on the properties of gadolinium-doped barium cerate

Cited by 51 publications

References 5 publications

Thermodynamics of hydration and oxidation in the proton conductor Gd-doped barium cerate from density functional theory calculations

Thermodynamics of hydration and oxidation in the proton conductor Gd-doped barium cerate from density functional theory calculations

Synthesis and Evaluation of Ni Catalysts Supported on BaCe0.5Zr0.3−xY0.2NixO3−δ with Fused-Aggregate Network Structure for the Hydrogen Electrode of Solid Oxide Electrolysis Cell

Preparation of doped BaZrO3 and BaCeO3 from nanopowders

Contact Info

Product

Resources

About