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@PHDTHESIS{Volkov:320084,
      author       = {Volkov, Sergey},
      othercontributors = {Stierle, Andreas},
      title        = {{O}perando {X}-ray {I}nvestigation of {S}olid {O}xide
                      {F}uel {C}ell {M}odel {E}lectrodes},
      school       = {Universität Hamburg},
      type         = {Dr.},
      address      = {Hamburg},
      publisher    = {Verlag Deutsches Elektronen-Synchrotron},
      reportid     = {PUBDB-2017-01522, DESY-THESIS-2017-011},
      series       = {DESY-THESIS},
      pages        = {120},
      year         = {2017},
      note         = {Universität Hamburg, Diss., 2016},
      abstract     = {A detailed study of three solid oxide fuel cells (SOFCs)
                      related model systems is presented in this work with the aim
                      of the better understanding of the structural changes in
                      cell components associated with their operation. The first
                      model system is an La$_{0.6}$Sr$_{0.4}$CoO$_{3−δ}$ (LSC)
                      on yttria-stabilized zirconia (YSZ). Changes in the YSZ(100)
                      single crystal surface structure buried under the squared
                      LSC microelectrode were studied at a synchrotron under
                      operational conditions. High flux photon beam at the
                      synchrotron allowed access to the LSC/YSZ interface.
                      Structural information from the substrate surface at an
                      atomic scale was acquired. Element-specific anomalous XRD
                      data allowed to distinguish between Y and Zr scattering
                      contributions. For the first time, it was shown that the Y
                      cation concentration at the electrode/elec- trolyte
                      interface strongly depends on the sample environment and the
                      applied potential. The second model system is a Pt/YSZ.
                      Buried YSZ(111) surface and dense Pt film morphology changes
                      under operational conditions were addressed. High-energy
                      X-rays were necessary to collect surface-sensitive
                      information from the interface due to highly absorbing Pt
                      film. The main conclusion is - under conditions applied, the
                      YSZ single crystal surface remains stable at an atomic
                      level. A nagging topic of the Pt "phase oxide" formation at
                      the Pt/YSZ interface during anodic polarization was also
                      raised. Although XRD data did not show a clear evidence of
                      PtO x presence at the interface, energy- dispersive X-ray
                      analysis of the film cross-cut profile after the synchrotron
                      experiment revealed distinct oxygen signal from delaminated
                      parts of the film. Last but not least, the structure of a
                      ZrO$_2$ ultrathin film grown on a Pt$_3$ Zr(0001) single
                      crystal was studied in ultra-high vacuum for the first time
                      be means of SXRD. This model system is aiming to improve
                      understanding of the electrolyte materials based on ZrO$_2$
                      (e.g. YSZ) at an atomic level. The results obtained, can be
                      summarized as follows: the oxide film is not stable at the
                      oxygen pressure higher than 10$^{−6}$mbar; the
                      density-functional theory models tend to overestimate the
                      film-substrate distance; there is more than 1ML of a
                      reconstructed Pt present in the top-most layer of the
                      Pt$_3$Zr(0001) beneath the zirconia film.},
      cin          = {FS-NL / DOOR},
      cid          = {I:(DE-H253)FS-NL-20120731 / I:(DE-H253)HAS-User-20120731},
      pnm          = {6213 - Materials and Processes for Energy and Transport
                      Technologies (POF3-621)},
      pid          = {G:(DE-HGF)POF3-6213},
      experiment   = {EXP:(DE-H253)Nanolab-03-20150101 /
                      EXP:(DE-H253)Nanolab-01-20150101 /
                      EXP:(DE-H253)Nanolab-02-20150101},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)29 / PUB:(DE-HGF)11},
      doi          = {10.3204/PUBDB-2017-01522},
      url          = {https://bib-pubdb1.desy.de/record/320084},
}