Fritz-Haber-Institut der Max-Planck-Gesellschaft  

Inorganic Chemistry – Electrochemistry Group

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Electrochemistry Group:
Sébastien Cap
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  Microwave hall effect (MHE)

Our latest achievements include the development of instrumentation for a contact-free and in situ method to quantify charge carrier concentrations and determine carrier mobilities. The method is based on the Microwave Hall Effect (MHE) and can differentiate between electrons and holes as charge carriers. Figure 1 shows results from typical MHE experiments obtained with n- and p-type germanium single crystals and ZnO powder as a function of the external magnetic field (B). Recently, the MHE setup has been extended to perform elevated temperature measurements and is currently in the last phase of validation. The synergy of the microwave cavity based techniques available in our group, i.e., EPR, MCPT, and MHE, offers a unique set of tools to characterize the charge transport across interfaces of thermally activated heterogeneous catalysts under relevant reaction conditions.

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Best Poster Prize of the 113th Bunsentagung for Christian Heine

At the 113th general assembly of the German Bunsen Society for Physical Chemistry, hold from 29th to 31st May 2014 at the University Hamburg, Germany, Christian Heine was awarded a Best Poster Prize for his poster " Facing the pressure gap in catalytic selective alkane oxidation" (Authors: Christian Heine, Michael Hävecker, Maik Eichelbaum, Eugen Stotz, Frank Rosowski, Axel Knop-Gericke, Annette Trunschke, Robert Schlögl). Further information on the poster content can be found here  ... ››
The Intimate Relationship between Bulk Electronic Conductivity and Selectivity in the Catalytic Oxidation of n-Butane

Maik Eichelbaum, Michael Hävecker, Christian Heine, Andrey Karpov, Cornelia-Katharina Dobner, Frank Rosowski, Annette Trunschke, and Robert Schlögl

Angew. Chem. Int. Ed. 51 (2012) 6246–6250.
DOI: 10.1002/anie.201201866 and 10.1002/ange.201201866.

  • Charge transport measurements with 2- or 4-contact electrical conductivity method on powder catalysts in fixed bed reactor difficult

  • First successful application of the contactfree microwave conductivity technique to the investigation of a VPO catalyst in the selective oxidation of n-butane to maleic anhydride

  • Linear correlation between conductivity and formation rate of maleic anhydride identified upon changing the gas hourly space velocity

  • Conductivity correlates also with gas phase dependent vanadium oxidation state as determined by in situ X-ray photoelectron spectroscopy

Abstract online   ... ››

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