Proton and apparent hydride ion conduction in Al-substituted SrTiO3

Widerøe, Marius; Münch, W.; Larring, Yngve; Norby, Truls

doi:10.1016/s0167-2738(02)00702-6

Cited by 34 publications

(27 citation statements)

References 11 publications

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“…There have been some speculations about the existence and transport of hydride ions (H -) in oxides under reducing conditions, but according to thermodynamic data of hydrides, the conditions for a hydrogen-separation membrane will be much too oxidizing for hydride ions to be stable [9]. Moreover, the apparent indications of hydride ions in the literature have now been rationalised by other, more credible phenomena, actually arising from transport of neutral hydrogen [2].…”

Section: What About Hydride Ions?mentioning

confidence: 99%

Dense Ceramic Membranes for Hydrogen Separation

Norby

Haugsrud

2007

Membranes for Energy Conversion

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Section: What About Hydride Ions?mentioning

confidence: 99%

Dense Ceramic Membranes for Hydrogen Separation

Norby

Haugsrud

2007

Membranes for Energy Conversion

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“…3 The role of H impurities in perovskite-type oxides are currently under intensive study. 8,13,[15][16][17][18][19][20][21] Effects of cation doping on vibrational frequencies and activation energies have also been extensively studied [10][11][12][13]15,16 but effects of V O on the diffusion of H have not been given the same attention, even though V O is considered to be closely related to proton generation processes. In perovskite-type oxides, proton intercalation is regarded to be the result of dissociative absorption of gaseous water filling an oxygen vacancy ͑V O ͒ with a hydroxide ion while the remaining proton occupies an interstitial site.…”

Section: Introductionmentioning

confidence: 99%

Negatively charged hydrogen at oxygen-vacancy sites in BaTiO3: Density-functional calculation

Iwazaki¹,

Suzuki²,

Tsuneyuki³

2010

Journal of Applied Physics

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Native defects and oxygen and hydrogen-related defect complexes in CdTe: Density functional calculations J. Appl. Phys.With a specific focus on defects formed from H atoms and oxygen vacancies ͑V O ͒ in perovskite-type oxide, stability and stable valence states of complex defects formation processes within BaTiO 3 are studied by using first-principle density-functional theory calculations. In our findings, H atoms diffuse as protons ͑H + ͒ into interstitial sites in BaTiO 3 , whereas these atoms when trapped at centers of V O sites convert to negatively ionized states ͑H − ͒. We also find that H atom trapping at V O sites occurs only in n-type carrier-rich environments without carrier compensation of V O 2+ and H + . If carrier electrons are compensated, H + ions are excluded from V O 2+ sites due to the repulsive Coulomb potential existing between the H + ion and the positively charged V O 2+ site. Difficulties in the calculation of the diffusion-energy diagram for H atoms, involving essential changes in the stable valence states during the diffusion process, are discussed and a practical solution is presented.

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“…Doping with aliovalent elements on A or/and B sites has the possibility to improve the electronic and/or ionic conductivity of SrTiO 3 via the introduction of various ionic and electronic defects [14,15]. Doping donors such as La 3+ on the Sr 2+ site and Nb 5+ on the Ti 4+ site convert SrTiO 3 into a highly semiconducting n-type material [16,17], while doping acceptors such as Fe 3+ , Co 3+ and Al 3+ on the Ti 4+ site obtain a p-type material [18][19][20][21]. The fuel cell tests with La x Sr 1 − x TiO 3 anodes demonstrated the potential ability of doped SrTiO 3 to be used as SOFC anodes [15].…”

Section: Introductionmentioning

confidence: 99%