% 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”.

@INPROCEEDINGS{Ackermann:878631,
      author       = {Ackermann, Jörg and Granwehr, Josef},
      othercontributors = {Streun, Matthias and Merz, Steffen and Eichel, Rüdiger-A.},
      title        = {{M}agnetic {R}esonance {T}echniques to {S}tudy {P}orous
                      {E}lectrodes and {E}lectrode {S}urfaces},
      school       = {RWTH Aachen},
      reportid     = {FZJ-2020-02962},
      year         = {2020},
      abstract     = {Nuclear Magnetic Resonance (NMR) is a unique analytical
                      tool to study molecular properties of various materials
                      indestructively. Observable parameters include chemical
                      structure, molecular motion, diffusion and various exchange
                      processes. Moreover, these parameters may be resolved
                      spatially over a region of interest with a resolution up to
                      50 µm employing Magnetic Resonance Imaging (MRI).
                      Fundamental elements in MR techniques are magnetic fields
                      and radio frequency irradiation.Thus, NMR is an attractive
                      tool to study chemical processes in and at porous
                      electrodes. Such electrodes are employed to convert
                      electrical energy to chemical energy. A detailed
                      understanding of the processes occurring during electrolysis
                      is key to a rational approach in efficiency
                      optimization.However, electrically conductive materials pose
                      additional challenges in NMR: i) NMR measurements need to be
                      performed at particular frequencies and the resonance mode
                      of the sensor coil must be adjusted accordingly.
                      Introduction of conductive samples in the sensor coil
                      strongly shift its resonance mode and often render
                      commercial probes untunable. Thus, custom probe head designs
                      offering a large tuning range are needed. ii) Radio
                      frequency eddy currents in conductive materials distort the
                      exciting field.iii) The radio frequency response from the
                      sample is distorted in the same way as the exciting
                      field.This talk provides an introduction into NMR on
                      electrically conductive samples. The effect of mode shifts
                      upon sample change and its implications are discussed. Using
                      different model systems, distortions in the exciting radio
                      frequency field are visualized. The strength of these
                      distortions is analyzed with respect to material type and
                      thickness. It is shown that thin metal layers neither
                      significantly perturb qualitative information in NMR
                      spectra, nor relaxometric or diffusometric information. It
                      is shown that radio frequency field distortion can be
                      advantageous as an additional spectroscopic dimension,
                      although most often regarded as a nuisance in literature.},
      month         = {Jun},
      date          = {2020-06-23},
      organization  = {Fuel Science: From Production to
                       Propulsion 8th International Conference
                       of the Cluster of Excellence “The
                       Fuel Science Center”, Aachen
                       (Germany), 23 Jun 2020 - 25 Jun 2020},
      subtyp        = {After Call},
      cin          = {IEK-9 / ZEA-2},
      cid          = {I:(DE-Juel1)IEK-9-20110218 / I:(DE-Juel1)ZEA-2-20090406},
      pnm          = {134 - Electrolysis and Hydrogen (POF3-134) / 131 -
                      Electrochemical Storage (POF3-131)},
      pid          = {G:(DE-HGF)POF3-134 / G:(DE-HGF)POF3-131},
      typ          = {PUB:(DE-HGF)6},
      url          = {https://juser.fz-juelich.de/record/878631},
}