Untitled

Haile, Sossina M.; Staneff, Geoff D.; Ryu, Ki‐Hyun

doi:10.1023/a:1004877708871

Cited by 329 publications

(190 citation statements)

References 38 publications

Supporting

Mentioning

183

Contrasting

Order By: Relevance

“…Many oxides with high conductivity (e.g., BaCeO 3 −derived compounds) are often unstable and susceptible to reaction with CO 2 and H 2 O, forming insulating carbonates and hydroxides [27]. This may be overcome by doping highly conducting oxides to improve stability (e.g., Zr-doped cerates) [28], improving the conductivity of more chemically stable oxides by reducing grain boundary resistance [29], by composite design, or by developing new alternatives (e.g., pyrochlores without any Ba or Sr) [13].…”

Section: Key Criteria Of Proton Conductors To Separate Hmentioning

confidence: 99%

“…However, any degradation in the membrane would lead to a decrease in the H 2 flux rate. The reverse may be said to be true of zirconate oxides (e.g., BaZrO 3 ), which, despite exhibiting high chemical stability, have low conductivity and require high sintering temperatures to achieve dense structures free of pores [28]. Often, however, it is possible to achieve a compromise between the proton conductivity and chemical stability (for use as H 2 separation membranes), by preparing mixed solid solutions of BaCeO 3 and BaZrO 3 .…”

Section: Perovskitesmentioning

confidence: 99%

See 1 more Smart Citation

Review of proton conductors for hydrogen separation

Phair

Badwal

2006

Ionics

223

132

View full text Add to dashboard Cite

There is a global push to develop a range of hydrogen technologies for timely adoption of the hydrogen economy. This is critical in view of the depleting oil reserves and looming transport fuel shortage, global warming, and increasing pollution. Molecular hydrogen (H 2 ) can be generated by a number of renewable and fossil-fuel-based resources. However, given the high cost of H 2 generation by renewable energy at this stage, fossil or carbon fuels are likely to meet the short-to medium-term demand for hydrogen. In view of this, effective technologies are required for the separation of H 2 from a gas feed (by-products of coal or bio-mass gasification plants, or gases from fossil fuel partial oxidation or reforming) consisting mainly of H 2 and CO 2 with small quantities of other gases such as CH 4 , CO, H 2 O, and traces of sulphur compounds. Several technologies are under development for hydrogen separation. One such technology is based on ion transport membranes, which conduct protons or both protons and electrons. Although these materials have been considered for other applications, such as gas sensors, fuel cells and water electrolysis, the interest in their use as gas separation membranes has developed only recently. In this paper, various classes of proton-conducting materials have been reviewed with specific emphasis on their potential use as H 2 separation membranes in the industrial processes of coal gasification, natural gas reforming, methanol reforming and the watergas shift (WGS) reaction. Key material requirements for their use in these applications have been discussed.

show abstract

Section: Key Criteria Of Proton Conductors To Separate Hmentioning

confidence: 99%

Section: Perovskitesmentioning

confidence: 99%

Review of proton conductors for hydrogen separation

Phair

Badwal

2006

Ionics

223

132

View full text Add to dashboard Cite

show abstract

“…Nd 3ϩ ) at the A-site; such doping would not create the oxygen vacancies that are required for proton uptake. In this context, Haile et al 4 find that A-site deficiency in alkaline-earth cerates and zirconates encourages dopant incorporation onto the A-site, rather than the intended M-site, reducing the concentration of oxygen vacancies. Recent studies 4 There has also been debate as to whether there is any significant association between the dopant ion and the protonic defect (hydroxy ion at oxygen site), which may affect proton mobility.…”

Section: Dopant Site-selectivity and Defect Association In Azro 3 Promentioning

confidence: 99%

Doping and defect association in AZrO3(A = Ca, Ba) and LaMO3(M = Sc, Ga) perovskite-type ionic conductors

et al. 2004

View full text Add to dashboard Cite

Computer simulation techniques have been used to investigate the defect chemistry of perovskite-structured ionic conductors based upon AZrO 3 (A = Ca, Ba) and LaMO 3 (M = Sc, Ga). Our studies have examined dopant site-selectivity, oxide ion migration and dopant-defect association at the atomic level. The energetics of dopant incorporation in AZrO 3 show strong correlation with ion size. We predict Y 3ϩ to be one of the most favourable dopants for BaZrO 3 on energetic grounds, which accords with experimental work where this cation is the commonly used acceptor dopant for effective proton conduction. Binding energies for hydroxy-dopant pairs in BaZrO 3 are predicted to be favourable with the magnitude of the association increasing along the series Y < Yb < In < Sc. This suggests that proton mobility would be very sensitive to the type of acceptor dopant ion particularly at higher dopant levels. Oxygen vacancy migration in LaScO 3 is via a curved pathway around the edge of the ScO 6 octahedron. Dopant-vacancy clusters comprised of divalent dopants (Sr, Ca) at the La site have significant binding energies in LaScO 3 , but very low energies in LaGaO 3 . This points to greater trapping of the oxygen vacancies in doped LaScO 3 , perhaps leading to higher activation energies at increasing dopant levels in accord with the available conductivity data.

show abstract

“…Therefore the driving force for the evolution towards a symmetric structure is increased and it becomes more difficult to distort the perovskite structure. This also show that stability in water vapor increases with decreasing ionic radius of the codopant [12,23].…”

Section: X-ray Diffraction (Xrd) Analysis:-mentioning

confidence: 82%

STRUCTURAL, DIELECTRIC AND A.C. CONDUCTIVITY STUDIES OF BaCe0.65 Zr0.2Y0.15O3-δ SOLID OXIDE FUEL CELL ELECTROLYTE BY CITRATE EDTA COMPLEXING SOL-GEL PROCESS.

Sailaja¹,

Murali²,

Babu³

et al. 2016

IJAR

View full text Add to dashboard Cite

This paper reports on the effect of Zirconium doping on BaCe 0.85 Y 0.15 O 3-δ electrolyte prepared using the citrate-EDTA complexing modified sol-gel process at calcinations temperature T=1000°C. The phase formation, Thermal analysis, Morphology, Stability and Conductivity measurements were performed on the sintered powders through Thermogravimetric analysis (TGDTA), Xray diffraction (XRD), Scanning electron microscope (SEM), EDAX, FTIR, RAMAN and LCR measurements. The crystallite size of the ceramic powders calculated from Scherrer equation is 26.49nm and microstructure of the sintered powder revealed that the average grain size is in the range of 2-3m. Dense ceramic materials were obtained at 1300°C and the relative density is 90% of the theoretical density. The ionic conductivity of the pellet is investigated from room temperature to 500°C and is found to exhibit highest conductivity of 2.2x10 -3 S/cm and 2.76 x10 -3 S/cm at 500°C in dry air and wet air atmosphere with 3% relative humidity. Frequency dependence on the dielectric constant has been investigated at various temperatures which clarified that larger value of ε ′ is due to superposition of both electrolyte -electrode interfacial and space charge polarization originated from dopant-vacancies created. The conductivity increased as temperature increases with activation energy in the range 0.5eV and hence this composition is worth being an electrolyte.

show abstract

Untitled

Cited by 329 publications

References 38 publications

Review of proton conductors for hydrogen separation

Review of proton conductors for hydrogen separation

Doping and defect association in AZrO3(A = Ca, Ba) and LaMO3(M = Sc, Ga) perovskite-type ionic conductors

STRUCTURAL, DIELECTRIC AND A.C. CONDUCTIVITY STUDIES OF BaCe0.65 Zr0.2Y0.15O3-δ SOLID OXIDE FUEL CELL ELECTROLYTE BY CITRATE EDTA COMPLEXING SOL-GEL PROCESS.

Contact Info

Product

Resources

About