Concentration and transport of protons in oxides

“…[4][5][6][7] In some studies binary oxides with fluoritelike structure and ternary oxides with pyrochloric structure have been studied as well. 8 Acceptor doped barium cerate shows the highest protonic conductivities but poor chemical stability. BaCeO 3 and SrCeO 3 are thermodynamically only weakly stabilized and the formation of carbonates takes place in the presence of CO 2 .…”

mentioning

confidence: 99%

Comparative Study of BaY_0.1Zr_0.9O_3-δProtective Layers Deposited to BaY_0.1Ce_0.9O_3-δMembrane Using Ultrasonic Spray Pyrolysis and Magnetron Sputtering Methods

Maide

Korjus

Vestli

et al. 2016

J. Electrochem. Soc.

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To combine chemical stability of BaY 0.1 Zr 0.9 O 3-δ (BZY) and good proton conductive properties of BaY 0.1 Ce 0.9 O 3-δ (BCY) bilayer membranes were prepared. Supportive BCY membranes were prepared applying dry pressing of nanopowder, which was synthesized with ultrasonic spray pyrolysis method. Thin protective BZY coatings were prepared using ultrasonic spray pyrolysis and magnetron sputtering methods. Ultarsonic spray pyrolyzed BZY layers were 0.5-1.1 μm thick, phase pure and with some closed porosity. Protective BZY layers synthesized with reactive magnetron sputtering method were approximately 0.7 μm thick, highly dense and with good phase purity. Activation energy for BCY membrane was 0.35 eV. BZY protective layer sintered at relatively low temperatures (600 to 1150 • C) had minor influence on total activation energy. Sintering at 1350 • C led to a decrease of activation energy of proton transport process at grain boundary region, an increase of activation energy of proton transport in bulk and a slight increase of total activation energy. Sintering at 1350 • C and higher temperatures led to interdiffusion of Zr and Ce cations between BZY and BCY phases and changes in chemical as well as electrochemical properties. Prepared membranes with BZY layer were exposed to CO 2 at 700 • C and were observed to be chemically stable if sintering of BZY were carried out at 1150 • C and lower temperatures. High temperature proton conductive (HTPC) oxide membranes have a variety of applications, such as hydrogen sensors for detecting hydrogen in gases and in melted metals, 1,2 detection systems of hydrocarbons in natural gas, devices for hydrogen extraction and precise pumping, reactors for electrochemical hydrogenation, dehydrogenation and production of ammonia 1-3 etc. Furthermore, these membranes can be used in fuel cells as well as in electrolyzers having some advantages in comparison with oxide ion conductive membranes: a) hydrogen and water are not mixed in fuel cell nor in electrolysis regime and b) higher conductivity and lower activation energy at intermediate temperatures compared with conventional oxide ion conductors.A variety of different chemical compositions has been tested as potential HTPC oxide membrane materials. For example, Ba-, Sr-, Gd-, La-, and Ca -cerates, zirconates, stannates, niobates and titanates, which are doped with Y, In, Gd, Sm, Sc, Ga . [4][5][6][7] In some studies binary oxides with fluoritelike structure and ternary oxides with pyrochloric structure have been studied as well.8 Acceptor doped barium cerate shows the highest protonic conductivities but poor chemical stability. BaCeO 3 and SrCeO 3 are thermodynamically only weakly stabilized and the formation of carbonates takes place in the presence of CO 2 . The stability with respect to the formation of carbonates and hydroxides increases in the order of materials: cerate < zirconate < titanate, i.e., opposite to the direction of the increase of stability of protonic defects and as the B site cation electronegativity increases. Some ...

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“…Almost another two decades passed before oxides were synthesized that combined high proton conductivity with high thermodynamic stability. [186][187][188] This brought these materials closer to a realistic alternative for fuel-cell applications and, hence, their transport properties are reviewed here.…”

mentioning

confidence: 99%

“…131,187 Similar to hydrogen-bonded networks, any reduction in symmetry may decrease the proton conductivity in oxides. This effect has been investigated in detail by comparing structural and dynamical features of protonic defects in yttrium-doped BaCeO 3 and SrCeO 3 203 and SrZrO 3 .…”

mentioning

confidence: 99%

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

Kreuer¹,

Paddison²,

Spohr³

et al. 2004

ChemInform

126

193

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Concentration and transport of protons in oxides

Cited by 163 publications

References 50 publications

Protonic defects and water incorporation in Si and Ge-based apatite ionic conductors

Protonic defects and water incorporation in Si and Ge-based apatite ionic conductors

Comparative Study of BaY_0.1Zr_0.9O_3-δProtective Layers Deposited to BaY_0.1Ce_0.9O_3-δMembrane Using Ultrasonic Spray Pyrolysis and Magnetron Sputtering Methods

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

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Concentration and transport of protons in oxides

Cited by 163 publications

References 50 publications

Protonic defects and water incorporation in Si and Ge-based apatite ionic conductors

Protonic defects and water incorporation in Si and Ge-based apatite ionic conductors

Comparative Study of BaY0.1Zr0.9O3-δProtective Layers Deposited to BaY0.1Ce0.9O3-δMembrane Using Ultrasonic Spray Pyrolysis and Magnetron Sputtering Methods

Transport in Proton Conductors for Fuel‐Cell Applications: Simulations, Elementary Reactions, and Phenomenology

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Comparative Study of BaY_0.1Zr_0.9O_3-δProtective Layers Deposited to BaY_0.1Ce_0.9O_3-δMembrane Using Ultrasonic Spray Pyrolysis and Magnetron Sputtering Methods