New Electrocatalysts with Pyrolyzed Siloxane Matrix
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In a first screening, platinum nanoparticles in pyrolyzed siloxane matrices with additional carbon fillers were developed and tested for their use as electrocatalysts. The influence of various parameters - type of carbon filler, carbon content, pyrolysis temperature, and siloxane composition - on structural properties and on electrochemical activity was investigated. Homogeneous distributions of platinum nanoparticles could be obtained for most of these electrocatalysts. Uniform platinum particles were generated with average particle sizes of 2.5–4.7 nm. At a temperature of 300 °C, the siloxane-based electrocatalysts exhibit high thermal stabilities with maximum weight losses of around 8 wt% after 20 h. The electrochemical behavior of the siloxane-based electrocatalysts in contact with 0.1 M H2SO4 was studied by cyclic voltammetry. Electrocatalytic activities were studied by CO adlayer oxidation, which also served for determining the electrochemical active surface area. High electrochemically active surface areas with up to 50 m2 g−1 Pt were obtained, which are in the same range as carbon-based electrocatalysts. Interestingly, some siloxane-based electrocatalysts showed a slightly higher catalytic activity for CO adlayer oxidation than carbon-based materials.
KeywordsElectrocatalyst Siloxane Pt nanoparticles Cyclic voltammetry CO oxidation HT-PEM fuel cells
This work was financed by the “Förderprogramm Angewandte Umweltforschung” of the federal state Bremen, Germany. Further support was given by the German Research Foundation (DFG) within the Research Training Group 1375 “Nonmetallic Porous Structures for Physical-Chemical Functions.” We thank Oliver Oppermann from the Institute of Solid State Physics at the University of Bremen for the TEM images. Further, support through the EU-project CATAPULT (GA-No. 325268) is acknowledged.
- 20.G. Jerkiewicz, G. Vatankhah, J. Lessard, M.P. Soriaga, Y.S. Park, Electrochim. Acta 49 (1451) (2004)Google Scholar