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Volumn 114, Issue 7, 2010, Pages 3017-3027

Pathways for oxygen incorporation in mixed conducting perovskites: A DFT-based Mechanistic analysis for (La, Sr)MnO3-δ

Author keywords

[No Author keywords available]

Indexed keywords

CATHODE MATERIALS; CUBIC UNIT CELLS; DFT CALCULATION; ELECTROSTATIC REPULSION; FUEL CELL OPERATION; HIGH TEMPERATURE; MECHANISTIC ANALYSIS; NEGATIVE ADSORPTION; OXYGEN INCORPORATION; REACTION MECHANISM; STABLE SURFACES; SURFACE OXYGEN VACANCIES;

EID: 77649092366     PISSN: 19327447     EISSN: 19327455     Source Type: Journal    
DOI: 10.1021/jp909401g     Document Type: Article
Times cited : (171)

References (67)
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    • In this article the deviation from Langmuir's isotherm is quantified with a plate capacitor model (double layer of negatively charged adsorbates and compensating positive charges in the first materials layer). The situation can as well be regarded as mutual repulsion of the charged adsorbates.
    • Fleig, J.; Merkle, R.; Maier, J. Phys. Chem. Chem. Phys. 2007, 9, 2713. In this article the deviation from Langmuir's isotherm is quantified with a plate capacitor model (double layer of negatively charged adsorbates and compensating positive charges in the first materials layer). The situation can as well be regarded as mutual repulsion of the charged adsorbates.
    • (2007) Phys. Chem. Chem. Phys. , vol.9 , pp. 2713
    • Fleig, J.1    Merkle, R.2    Maier, J.3
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    • -) if the formal charges are used.
    • -) if the formal charges are used.
  • 36
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    • 2)
    • 2)
  • 38
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    • and references therein
    • Poulsen, F. W. Solid State Ionics 2000, 129, 145, and references therein.
    • (2000) Solid State Ionics , vol.129 , pp. 145
    • Poulsen, F.W.1
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    • r
    • r.
  • 41
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    • 2 are completely lost.
    • 2 are completely lost.
  • 44
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    • Please note that the levels of coverage calculated here are equilibrium values. While they will be valid also for small deviations from equilibrium (e.g., in ac impedance measurements with sufficiently small excitation amplitude), their values will deviate under nonequilibrium conditions (large dc bias) and in this case also will depend on the reaction mechanism and its rate-determining step, see
    • Please note that the levels of coverage calculated here are equilibrium values. While they will be valid also for small deviations from equilibrium (e.g., in ac impedance measurements with sufficiently small excitation amplitude), their values will deviate under nonequilibrium conditions (large dc bias) and in this case also will depend on the reaction mechanism and its rate-determining step, see: Fleig, J. Phys. Chem. Chem. Phys. 2005, 7, 2027.
    • (2005) Phys. Chem. Chem. Phys. , vol.7 , pp. 2027
    • Fleig, J.1
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    • 77649124991 scopus 로고    scopus 로고
    • 2-2 corresponds to an orientation with the O-O bond parallel to the Mn-O bonds
    • 2-2 corresponds to an orientation with the O-O bond parallel to the Mn-O bonds.
  • 50
    • 77649094655 scopus 로고    scopus 로고
    • 1-δ remains valid.
    • 1-δ remains valid.
  • 51
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    • There are several repulsive and attractive interactions between charged adsorbates and surface VO . The repulsion between the two Oadsorbed on neighboring Mn (final state of section B) is + 0.05 eV; this small value has no significant effect on barriers. The attraction of O- adsorbed on Mn andVO is 0.7 eV, and for V-O- 2 and VO -O2- 2 similar values are expected. Attractive interactions of this magnitude might lower reaction barriers, especially for the last step of the mutual approach where the strongest change of attraction energy is expected. On the other hand, if the approach comprises many jumps at larges distances, the acceleration of the last jump will hardly change the rate. The attraction energy of 0.7 eV may seem to be rather high, but it is still within the range of defect interactions of 0.4-0.9 eV observed in the bulk of BaZrO3 between M'Zr dopants and VO given
    • Zr dopants and VÖ given in Sundell, P. G.; Björketun, M. E.; Wahnström, G. Phys. Rev. B 2006, 73, 104112.
    • (2006) Phys. Rev. B , vol.73 , pp. 104112
    • Sundell, P.G.1    Björketun, M.E.2    Wahnström, G.3
  • 52
    • 77649142320 scopus 로고    scopus 로고
    • When we denote the (surface) oxygen vacancy as VÖ, this is not intended to make a strict statement about its charge state. Since the bonding has a significant degree of covalency, neither the charge of the oxide ion nor of the oxygen vacancy is exactly 2- or 2+
    • When we denote the (surface) oxygen vacancy as VÖ, this is not intended to make a strict statement about its charge state. Since the bonding has a significant degree of covalency, neither the charge of the oxide ion nor of the oxygen vacancy is exactly 2- or 2+.
  • 53
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    • Ö, and the contribution of the respective barrier to the overall activation energy is lowered accordingly
    • 2 may still be valid.
  • 54
    • 77649145642 scopus 로고    scopus 로고
    • A nudged elastic band calculation with moderate resolution could not detect a barrier for step D2; thus, the barrier is definitely below 0.3 eV. Therefore, it does not significantly impede the kinetics
    • A nudged elastic band calculation with moderate resolution could not detect a barrier for step D2; thus, the barrier is definitely below 0.3 eV. Therefore, it does not significantly impede the kinetics.
  • 55
    • 77649120180 scopus 로고    scopus 로고
    • Ö which costs 0.9 + 1.5 eV ) 2.4 eV. This process is even less favorable than direct O- diffusion.
    • Ö which costs 0.9 + 1.5 eV ) 2.4 eV. This process is even less favorable than direct O- diffusion.
  • 56
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    • 10
    • 10
  • 57
    • 0032652515 scopus 로고    scopus 로고
    • 2, since this charge transfer generates the sensor signal in Taguchi-type gas sensors typically operated at 473- 573 K). We adopt a value of 0.1 which was found to be the upper limit for strong oxygen chemisorption on Pt; see: Mitterdorfer, A.; Gauckler, L. J. Solid State Ionics 1999, 117, 203; Solid State Ionics 1999, 120, 211.
    • 2, since this charge transfer generates the sensor signal in Taguchi-type gas sensors typically operated at 473- 573 K). We adopt a value of 0.1 which was found to be the upper limit for strong oxygen chemisorption on Pt; see: Mitterdorfer, A.; Gauckler, L. J. Solid State Ionics 1999, 117, 203; Solid State Ionics 1999, 120, 211
  • 58
    • 77649141574 scopus 로고    scopus 로고
    • The overestimation of the oxidation enthalpy can to a certain degree be traced back to the "DFT error" of 0.7 eV per O. While this correction would significantly improve the value of the overall oxidation enthalpy, it is difficult to apply it in a consistent way to all other intermediates and transitions states which occur between the oxidized (perfect) surface and the oxygen-deficient surface. In order not to distort the energy profile arbitrarily, we refrain from applying this correction for the data used as the basis of the kinetic treatment
    • The overestimation of the oxidation enthalpy can to a certain degree be traced back to the "DFT error" of 0.7 eV per O. While this correction would significantly improve the value of the overall oxidation enthalpy, it is difficult to apply it in a consistent way to all other intermediates and transitions states which occur between the oxidized (perfect) surface and the oxygen-deficient surface. In order not to distort the energy profile arbitrarily, we refrain from applying this correction for the data used as the basis of the kinetic treatment.
  • 62
    • 0032184465 scopus 로고    scopus 로고
    • 0 is the area-normalized oxygen exchange rate; see, e.g.
    • 0 is the area-normalized oxygen exchange rate; see, e.g.: Maier, J. Solid State Ionics 1998, 112, 197.
    • (1998) Solid State Ionics , vol.112 , pp. 197
    • Maier, J.1
  • 66
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    • -0.34
    • -0.34.
  • 67
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    • Ö] which also originates in the too negative DFT oxidation enthalpy
    • Ö] which also originates in the too negative DFT oxidation enthalpy.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.