Mechanical and dielectric relaxation studies on the mechanism of oxygen ion diffusion inLa2Mo2O9

2002 ◽  
Vol 65 (6) ◽  
Author(s):  
X. P. Wang ◽  
Q. F. Fang
Keyword(s):  
Dielectric Relaxation ◽  
Ion Diffusion ◽  
Oxygen Ion ◽  
Relaxation Studies ◽  
Oxygen Ion Diffusion

Influence of Tungsten Doping in La2Mo2O9 Oxide-Ion Conductors by Dielectric Relaxation Measurements

2011 ◽  
Vol 130-134 ◽  
pp. 3302-3305
Author(s):  
Dan Li ◽  
Xiang Hu Li
Keyword(s):  
Phase Transition ◽  
Dielectric Relaxation ◽  
Ion Diffusion ◽  
Ion Distribution ◽  
Β Phase ◽  
Oxygen Ion ◽  
Relaxation Measurements ◽  
Temperature Relaxation ◽  
Oxygen Ion Diffusion ◽  
Tungsten Doping

The effects of tungsten doping in La2Mo2–yWyO9 (y =0, 0.25, 0.5, 1.0, 1.4) samples were studied using dielectric relaxation measurements. The results indicate that the solubility of W6+ in La2Mo2O9 sample is about 25mol%, W6+ can suppress the α/β phase transition in the La2Mo2O9. Additional to the low-temperature relaxation peak Pd associated with oxygen ion diffusion, a new dielectric loss peak Ph associated with a phase transition from the static disordered state to the dynamic disordered state of oxygen ion distribution was observed around 740 K. The conductivity of La2Mo1.9W0.1O9 sample is higher than that of the pure La2Mo2O9, and then decrease with the increasing of the tungsten doping in La2Mo2–yWyO9 (y = 0.5, 1.0) samples in the whole measurement temperature.

scholarly journals Oxygen deficient layered double perovskite as an active cathode for CO2 electrolysis using a solid oxide conductor

2015 ◽  
Vol 182 ◽  
pp. 227-239 ◽  
Author(s):  
Tae Ho Shin ◽  
Jae-Ha Myung ◽  
Maarten Verbraeken ◽  
Guntae Kim ◽  
John T. S. Irvine
Keyword(s):  
Double Perovskite ◽  
Cathode Side ◽  
Layered Perovskite ◽  
Ion Diffusion ◽  
Oxide Electrode ◽  
Oxygen Ion ◽  
A Site ◽  
Oxygen Ion Diffusion ◽  
Co2 Electrolysis ◽  
A Current

A-site ordered PrBaMn2O5+δ was investigated as a potential cathode for CO2 electrolysis using a La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte. The A-site ordered layered double perovskite, PrBaMn2O5+δ, was found to enhance electrocatalytic activity for CO2 reduction on the cathode side since it supports mixed valent transition metal cations such as Mn, which could provide high electrical conductivity and maintain a large oxygen vacancy content, contributing to fast oxygen ion diffusion. It was found that during the oxidation of the reduced PrBaMn2O5+δ (O5 phase) to PrBaMn2O6−δ (O6 phase), a reversible oxygen switchover in the lattice takes place. In addition, here the successful CO2 electrolysis was measured in LSGM electrolyte with this novel oxide electrode. It was found that this PrBaMn2O5+δ, layered perovskite cathode exhibits a performance with a current density of 0.85 A cm−2 at 1.5 V and 850 °C and the electrochemical properties were also evaluated by impedance spectroscopy.

Werkstoffaufbau und diffusiver Stofftransport aufgezeigt an ausgewählten Beispielen / Material structure and diffusive mass transport as pointed out by means of selected examples

2000 ◽  
Vol 6 (4) ◽  
pp. 429-450
Author(s):  
R. Kriegel ◽  
A. Buchwald ◽  
Ch. Kaps
Keyword(s):  
Mass Transport ◽  
Diffusion Coefficients ◽  
Transport Mechanism ◽  
Diffusion Models ◽  
Second Law ◽  
Material Structure ◽  
Ion Diffusion ◽  
Oxygen Ion ◽  
Oxygen Ion Diffusion

Abstract The diffusive mass transport in materials is above all determined by the material structure. The experimental determination of diffusion coefficients is based on diffusion models, which results from special mathematical solutions of Fick's second law and its corresponding boundary conditions. The general usefulness of these diffusion models will be described using some examples, e. g. the diffusion of deteriorating salts in masonry materials, the oxygen ion diffusion in mixed conducting ceramics and the cation exchange in single crystals. The measurement of the diffusion coefficients results in a better comprehension of the transport mechanism as well as of the "morphology" of the transport medium, which allows to optimize the conditions of the mass transport and the material structure and composition, respectively.

scholarly journals Fast grain boundary oxygen ion diffusion in the α-phase of Bi2O3

2017 ◽  
Vol 299 ◽  
pp. 89-92 ◽  
Author(s):  
Richard J. Chater ◽  
Andrea Cavallaro ◽  
Ryan D. Bayliss ◽  
Stuart N. Cook ◽  
Bryan D. Esser ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Ion Diffusion ◽  
Oxygen Ion ◽  
Α Phase ◽  
Oxygen Ion Diffusion
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