Regensburg 2007 – wissenschaftliches Programm
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AKE: Arbeitskreis Energie
AKE 3: Solar and Hydrogen Technology, Fuel Cells
AKE 3.3: Vortrag
Montag, 26. März 2007, 17:15–17:30, H45
Synthesis and Magnetic Properties of Porphyrin-based Electrocatalysts for the Oxygen Reduction in a Fuel Cell — •Ulrike Ingrid Koslowski1, Sebastian Fiechter1, Klaus Lips1, Irmgard Abs-Wurmbach2, Jan Behrends1, Gerrit Schmithals1, and Peter Bogdanoff1 — 1Hahn-Meitner-Institut Berlin GmbH, Glienicker Str. 100, D-14109 Berlin — 2Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin
International research efforts have been made to find alternative catalysts instead of platinum for the ORR in fuel cells. N4-metallomacrocycles are well known as materials for the reduction of oxygen. Heat treatment of these materials impregnated on carbon black results in highly active catalysts [1].
We would like to introduce a new preparation technique: By using a foaming agent (such as iron oxalate) during the decomposition of the porphyrin a highly porous carbon matrix is formed in situ with integrated catalytic centres [2].
For both preparation methods (impregnation and using a foaming agent) only a diluted number of catalytic centres are formed in the carbon matrix. It is assumed that these centres are transition metal ions coordinated by nitrogen in graphene type layers. We suppose that there are also differences in the structure of both catalytic systems.
To compare and to characterise these methods Electron Paramagnetic Resonance (EPR) and 57Fe Mössbauer spectroscopic (MS) experiments were performed. Additional measurements will illustrate the differences of the macroscopic structure of both materials. [1] Top. Curr. Chem. 1976, 61, 133 [2] J. New. Mat. Electrochem. Sys. 2004, 7, 85