% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@BOOK{Seeger:141328,
      author       = {Seeger, Janka},
      title        = {{E}ntwicklung protonenleitender {W}erkstoffe und
                      {M}embranen auf {B}asis von {L}anthan-{W}olframat für die
                      {W}asserstoffabtrennung aus {G}asgemischen},
      volume       = {188},
      school       = {Universität Bochum},
      type         = {Dr.},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2013-06513},
      isbn         = {978-3-89336-903-4},
      series       = {Schriften des Forschungszentrums Jülich Reihe Energie $\&$
                      Umwelt / Energy $\&$ Environment},
      pages        = {130 S.},
      year         = {2013},
      note         = {Universität Bochum, Diss., 2013},
      abstract     = {Lanthanum tungstate La$_{6-x}$WO$_{12-\delta}$ (named LWO)
                      is a ceramic material with mixed protonic electronic
                      conductivity. Thereby it is a good candidate membrane
                      material for hydrogen separation from synthesis gas in a
                      fossil pre-combustion power plant. This work shows a
                      material optimization by substitution targeted to clearly
                      enhance the mixed conductivity and thereby the hydrogen flow
                      through the LWO membrane. The first part of the work shows
                      the synthesis and characterization of unsubstituted LWO. It
                      points out that monophase LWO powder can be reproducibly
                      synthesized. The La/W-ratio has to be considerably smaller
                      than the nominal ratio of La/W = 6.0. It also depends on the
                      used sintering conditions. Different relevant properties of
                      LWO like stability in conditions close to application,
                      thermal expansion, sintering behavior or microstructure were
                      determined. Furthermore, the electrical conductivity of the
                      material was investigated. LWO exhibits a prevailing
                      protonic conductivity up to 750 °C in wet atmospheres.
                      Under dry atmospheres n-type conductivity was dominating.
                      Oxygen ion and n-type conductivity dominated in wet and dry
                      atmospheres above 750 °C. The main part of the work is
                      concerned with the development of new LWO based materials by
                      substitutions. The aim is to achieve an improved mixed
                      protonic electronic conductivity. Substitution elements for
                      lanthanum side were Mg, Ca, Sr, Ba, Ce, Nd, Tb, Y and Al,
                      while for the tungsten side Mo, Re and Ir were used. The
                      total conductivity of the developed materials was
                      investigated and compared to that of the unsubstituted LWO.
                      The substitution of lanthanum led to no appreciable
                      enhancement of the conductivity whereas the substitution of
                      tungsten with 20 mol\% molybdenum or 20 mol\% rhenium
                      clearly improved it. This caused a hydrogen flow about seven
                      times higher for 20 mol\% molybdenum- and about ten times
                      higher for 20 mol\% rhenium-substituted LWO in comparison
                      with the unsubstituted LWO at 700 °C. In the last part of
                      the work first asymmetric membranes consisting of a thin
                      functional layer and a supporting substrate to enhance the
                      hydrogen flow by reducing the membrane thickness were
                      developed. It succeeded in manufacturing gastight samples.
                      However the samples became highly curved during the
                      sintering. Therefore, further intensive component
                      development will be required.},
      cin          = {IEK-1},
      cid          = {I:(DE-Juel1)IEK-1-20101013},
      pnm          = {122 - Power Plants (POF2-122)},
      pid          = {G:(DE-HGF)POF2-122},
      typ          = {PUB:(DE-HGF)3},
      url          = {https://juser.fz-juelich.de/record/141328},
}