@article{MunteanRostPascaletal.2016, author = {Muntean, Roxana and Rost, Ulrich and Pascal, Dragos-Toader and Marginean, Gabriela and Vaszilcsin, Nicolae}, title = {Determination of the Electrochemical Surface Area for CNF-Pt Electrocatalyst Using Cyclic Voltammetry}, series = {Chemical Bulletin of "Politehnica" University of Timisoara, Romania}, volume = {61 (75)}, journal = {Chemical Bulletin of "Politehnica" University of Timisoara, Romania}, number = {2}, pages = {44 -- 48}, year = {2016}, abstract = {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.}, language = {en} } @article{MunteanRostMargineanetal.2016, author = {Muntean, Roxana and Rost, Ulrich and Marginean, Gabriela and Vaszilcsin, Nicolae}, title = {Optimisation of the Electrodeposition Parameters for Platinum Nanoparticles on Carbon Nanofibers Support}, series = {Solid state phenomena}, journal = {Solid state phenomena}, number = {254}, doi = {10.4028/www.scientific.net/SSP.254.153}, pages = {153 -- 158}, year = {2016}, abstract = {Platinum nanoparticles electrodeposition on carbon nanofibers (CNF) support has been performed with the purpose to obtain electrodes that can be further used especially in a polymer electrolyte membrane fuel cell (PEMFC). A pretreatment of CNF is required in order to enhance the surface energy, which simultaneously improves handling and wettability as well as interaction with the platinum cations. This step was performed using oxygen plasma functionalization. To produce CNF supported Pt catalysts, an electrochemical method was applied and the deposition parameters were adjusted to obtain nanosized platinum particles with a good distribution onto the graphitic surface. The morphology and structure of the obtained particles were investigated by scanning electron microscopy combined with energy dispersive X-Ray spectroscopy. The amount of deposited platinum was established using thermogravimetrical measurements. Cyclic voltammetry performed in 0.5 M H2SO4 solution was applied for determining the electrochemical surface area (ECSA) of the obtained electrodes.The functionalization degree of the CNF outer surface has a strong influence on the structure, distribution and amount of platinum particles. Moreover, the current densities, which were set for the deposition process influenced not only the particles size but also the platinum amount. Applying an oxygen plasma treatment of 80 W for 1800 s, the necessary degree of surface functionalization is achieved in order to deposit the catalyst particles. The best electrodes were prepared using a current density of 50 mA cm-2 during the deposition process that leads to a homogenous platinum distribution with particles size under 80 nm and ECSA over 6 cm2}, language = {en} } @inproceedings{RostBrodmannZekornetal.2016, author = {Rost, Ulrich and Brodmann, Michael and Zekorn, Bruno and Peinecke, Volker and Radev, Ivan and Podleschny, Pit Yannick}, title = {PEM fuel cell electrode preparation using oxygen plasma treated graphene related material serving as catalyst support for platinum nanoparticles}, series = {Konferenz: 7. NRW Nano-Konferenz, 7.-8. Dezember 2016 in M{\"u}nster}, booktitle = {Konferenz: 7. NRW Nano-Konferenz, 7.-8. Dezember 2016 in M{\"u}nster}, pages = {1}, year = {2016}, abstract = {This experimental work deals with the preparation and investigation of PEM fuel cell electrodes, which are obtained using Graphene Related Material (GRM) serving as catalyst support material for platinum nanoparticles. The applied GRM belong to the group of carbon nanofibers and exhibits a helical-ribbon structure with dimensions of 50 nm in diameter and an average length up to a few µm. Furthermore, utilized GRM provide a superior graphitisation degree of about 100 \%, which leads to both high corrosion resistance and low ohmic resistance. Material stability plays one of the main roles for long term fuel cell operation, whereby a great electrical catalyst contact combined with high specific surface area yields in high fuel cell performances. Prior to GRM dispersion and deposition onto a gas diffusion layer, the graphene structures are functionalized by oxygen plasma treatment. Through this step, functional oxygen groups are generated onto the GRM outer surface providing an improved hydrophilic behaviour and facilitating the GRM suspension preparation. In addition, the oxygen groups act as anchors for platinum nanoparticles which are subsequently deposited onto the GRM surface through a pulse electrodeposition process. Membrane electrode assemblies produced with the prepared electrodes are investigated in-situ in a PEM fuel cell test bench.}, language = {de} }