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- carbon nanofibers, platinum electrodeposition, ele ctrochemical surface area (1)
- Cavitation; Corrosion; Laser remelting; Self-fluxing alloys; Stellite 6 (1)
- Erneuerbare Energien (1)
- Hydraulic compression, Carbon Nano Fibers, PEM Fuel Cells, Catalyst utilization (1)
- Hydrogen evolution reaction (1)
- Kohlenstoff-Nanoröhre (1)
- PEM fuel cell electrocatalysts, Carbon nanofibers, Oxygen plasma activation, Pulsed electroplating. (1)
- PEM water electrolysis (1)
- Polymer-Elektrolytmembran-Brennstoffzelle (1)
- PtCoMn (1)
Institut
Carbon Nanofibers (CNF) are considered to be a promising catalyst support material due to their unique characteristics, excellent mechanical, electrical and structural properties, high surface area and nevertheless, good interaction with metallic catalyst particles. The possibility of preparing CNF decorated with platinum by an electrochemical method was tested, using a hexachloroplatinic bath solution. The experiments were carried out with the aid of a Potentiostat/Galvanostat Ivium Technologies Vertex, in a three – electrode cell. The aim of the present work was to determine the electrochemical surface area (ECSA) of the CNF-Pt catalysts in relation to the functionalization treatment of fibers, using an electrochemical method. ECSA for different functionalized CNF-Pt catalysts was determined by cyclic voltammetry in 0.5 M H2SO4 solution. The highest active surface of platinum was obtained for the samples with CNF functionalized by plasma treatment using 80 W for 1800 s. The obtained results correlate very well with the particles size and distribution of platinum, revealed by scanning electron microscopy (SEM) and the quantity of deposited platinum determined by thermo gravimetrical analysis (TGA) respectively. Cyclic voltammetry (CV) has been proven to be a suitable method for estimation of the ECSA of the electrocatalysts.
For this study gas diffusion electrodes (GDE) with low platinum loading are prepared for the application as anode in polymer electrolyte membrane fuel cell (PEMFC) systems based on hydraulic compression. As catalyst support material, carbon nanofibers (CNF) are investigated because of their high specific surface area and high graphitization degree. The electrode preparation is optimized by an economic and environmental friendly pre-treatment process in oxygen plasma. For GDE manufacture an ink containing oxygen plasma activated CNFs as well as hydrophilic polymer is used. After spray coating of this CNF ink on a graphitic substrate, platinum is deposited using the pulse plating technique. Preliminary results showed a considerable improvement of CNF dispersibility as well as an increased amount and an optimized morphology of the deposited platinum. Morphology and microstructure are observed by scanning electron microscopy as well as transmission electron microscopy. Platinum loading is determined by thermogravimetric analysis to be in the range of 0.01 mg cm-2 to 0.017 mg cm-2. Furthermore, MEAs are prepared from these GDEs and testing is performed in a novel modular fuel cell test stack based on hydraulic compression. Technical information about stack design and functions is given in this work.