TY - JOUR A1 - Rost, Ulrich A1 - Brodmann, Michael A1 - Zekorn, Bruno A1 - Peinecke, Volker A1 - Radev, Ivan A1 - Podleschny, Pit Yannick T1 - PEM fuel cell electrode preparation using oxygen plasma treated graphene related material serving as catalyst support for platinum nanoparticles JF - Materials today. Proceedings N2 - This work deals with the preparation and investigation of polymer electrolyte membrane fuel cell (PEMFC) electrodes, which are obtained using gas diffusion layers coated with graphene related material (GRM) serving as a catalyst support for platinum nanoparticles. PEMFC electrocatalysts have been prepared by pulsed electrochemical deposition of platinum particles from hexachloroplatinic acid. Prior to GRM decoration with platinum, the graphene structures are functionalized by oxygen plasma treatment. This leads to oxygen containing functional groups on the GRM outer surface, providing an improved hydrophilic behavior, thus favoring the Pt deposition process. Membrane electrode assemblies (MEAs) with the so prepared electrodes are investigated in-situ in our fuel cell test system. Polarization plots (in-situ cell performance) using these MEAs have been tested under different operational conditions. Y1 - 2017 U6 - https://doi.org/10.1016/j.matpr.2017.09.195 SN - 2214-7853 VL - 4 IS - Supplement 2 SP - S249 EP - S252 ER - TY - JOUR A1 - Rost, Ulrich A1 - Muntean, Roxana A1 - Marginean, Gabriela A1 - Merino, Cesar A1 - Diez, Roberto A1 - Vaszilcsin, Nicolae A1 - Brodmann, Michael T1 - Effect of Process Parameters for Oxygen Plasma Activation of Carbon Nanofibers on the Characteristics of Deposited Platinum Nanoparticles as Electrocatalyst in Proton Exchange Membrane Fuel Cells JF - International Journal of Electrochemical Science N2 - In the polymer electrolyte membrane fuel cells (PEMFC) state of the art, rare and expensive platinum group metals (PGM) or PGM alloys are used as catalyst material. Reduction of PGMs in PEMFC electrodes is strongly required to reach cost targets for this technology. An optimal catalyst utilization is achieved in case of nano-structured particles supported on carbon material with a large specific surface area. In this study, graphitic material, in form of carbon nanofibers (CNF), is decorated with Pt particles, serving as catalyst material for PEMFC electrodes with low Pt loading. As a novelty, the effect of oxygen plasma treatment of CNFs previously to platinum particle deposition has been studied. Electrodes are investigated in respect of the optimal morphology, microstructure as well as electrochemical properties. Therefore, samples are characterized by means of scanning electron microscopy combined with energy dispersive X-ray analysis, transmission electron microscopy, thermogravimetry, X-ray diffraction as well as X-ray fluorescence analysis. In order to determine the electrochemical active surface area of catalyst particles, cyclic voltammetry has been performed in 0.5 M sulphuric acid. Selected samples have been investigated in a PEMFC test bench according to their polarization behavior. KW - PEM fuel cell electrocatalysts KW - Carbon nanofibers KW - Oxygen plasma activation KW - Pulsed electroplating. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1010-opus4-9509 SN - 1452-3981 VL - 2016 IS - Volume 11, Issue 11 SP - 9110 EP - 9122 PB - Elsevier ER - TY - JOUR A1 - Kazamer, Norbert A1 - Tack, Meike A1 - Spree, Mathias A1 - Underberg, Martin A1 - Rost, Ulrich A1 - Reichenberger, Sven A1 - Cieluch, Maximilian A1 - Salih, Haujin A1 - Wirkert, Florian Josef A1 - Böhm, Leonard A1 - Roth, Jeffrey A1 - Nallathambi, Varatharaja A1 - Gault, Baptiste A1 - Baer, Christoph A1 - Orend, Kerstin A1 - Barcikowski, Stephan A1 - Hülser, Tim A1 - Brodmann, Michael T1 - Ultrasonically Deposited Boron-Doped Silicon Decorated with Laser-Generated Iridium Nanoparticles as Manufacturing Approach for OER Electrodes in PEM Water Electrolysis JF - Advanced Materials Interfaces N2 - The study introduces flexible and scalable manufacturing approach for electrodes utilizing boron-doped silicon as conductive support for iridium nanoparticles, addressing the challenges of cost and scarcity associated with noble catalysts for oxygen evolution reaction (OER). Colloidal Ir nanoparticles are synthesized via pulsed-laser ablation (≈4–7 nm) and decorated on B-doped Si (≈100 nm) through electrostatic adsorption. Titanium substrates are ultrasonically sprayed with Si:B – Ir and Ir nanoparticles with very low iridium loading of 12 wt.%. Crystalline Ir phases (Ir(111), Ir(200)) are observed and known to enhance the OER mechanism. Additionally, atom probe tomography confirms that the Si support particles contained 0.03-0.5 at.% of boron throughout the entire particle, while electrical permittivity and through-plane measurements reveal a positive impact of B-doped Si on the electrical conductivity of the nanocatalysts and of the ultralow-loaded catalyst coated Ti substrates (0.12 mgIr cm−2), respectively. Rotating disk electrode results show pronounced oxidation peaks for decorated Ir nanoparticles. The Si:B-Ir 4 nm catalyst exhibits the highest turnover frequency (2.62 s−1) and a competitive electrochemical surface area (25 m2 gIr−1) compared to Si:B-Ir 7 nm (0.96 s−1; 37.5 m2 gIr−1) and Ir black (0.24 s−1; 5 m2 gIr−1). The overall analysis of the parameters highlights a performant catalytic efficiency, through balancing activity and reaction kinetics effectively. KW - PEM Water Electrolysis KW - OER Electrodes Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:1010-opus4-46883 VL - 2025 IS - Volume 12, Issue 8 PB - Wiley ER - TY - JOUR A1 - Wirkert, Florian Josef A1 - Roth, Jeffrey A1 - Rost, Ulrich A1 - Brodmann, Michael T1 - Hydraulic cell compression for performance preserving upscaling of PEM electrolyzers JF - International Journal of Smart Grid and Clean Energy N2 - The technology of polymer electrolyte membrane (PEM) electrolysis provides an efficient way to produce hydrogen. In combination with renewable energy sources, it promises to be one of the key factors towards a carbon-free energy infrastructure in the future. Today, PEM electrolyzers with a power consumption higher than 1 MW and a gas output pressure of 30 bar (or even higher) are already commercially available. Nevertheless, fundamental research and development for an improved efficiency is far from being finally accomplished, and mostly takes place on a laboratory scale. Upscaling the laboratory prototypes to an industrial size usually cannot be achieved without facing further problems and/or losing efficiency. With our novel system design based on hydraulic cell compression, a lot of the commonly occurring problems like inhomogeneous temperature and current distribution can be avoided. In this study we present first results of an upscaling by a factor of 30 in active cell area. KW - Hydraulic cell compression KW - PEM electrolysis KW - Upscaling laboratory models Y1 - 2017 U6 - https://doi.org/10.12720/sgce.6.3.171-176 SN - 2315-4462 VL - 6 IS - 3 SP - 171 EP - 176 ER - TY - CHAP A1 - Podleschny, Pit Yannick A1 - Muntean, Roxana A1 - Rost, Ulrich A1 - Brodmann, Michael T1 - PEM Fuel Cells Electrodes Preparation Using Oxygen Plasma Treated Graphene Related Material Serving as Catalyst Support for Platinum Nanoparticles T2 - Konferenz: NMWP Young Academics: Graphen und 2D-Materialien, 30.-31. August 2016 in Siegen N2 - 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. Y1 - 2016 N1 - Die orale Präsentation auf der NMWP Young Academics in Siegen (30.-31. August) hatte die Einladung zur 7. NRW Nanokonferenz (7.-8. Dezember) mit einem Poster und einem Paper zur Folge (vgl. auch: Rost, U.; Brodmann, M.; Zekorn, B.; Peinecke, V.; Radev, I.; Podleschny, P. (2016): PEM fuel cell electrode preparation using oxygen plasma treated graphene related material serving as catalyst support for platinum nanoparticles). Dabei war die Vorgabe, dass sich der Titel nicht ändern durfte. ER - TY - CHAP A1 - Rost, Ulrich A1 - Roth, Jeffrey A1 - Brodmann, Michael ED - Großmann, Uwe ED - Kunold, Ingo ED - Engels, Christoph T1 - Ein neuartiges Konzept für Hochdruckelektrolyseursysteme in modularer Bauweise zur Produktion von Wasserstoff aus Überschussenergie erneuerbarer Quellen T2 - Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015 N2 - Für einen Energiesektor, der zukünftig im hohen Maße auf erneuerbaren Quellen beruht, sind Energiespeicher unverzichtbar, um die heute gewohnte Versorgungssicherheit auch in Zeiten geringer Einspeisung aus Wasser, PV- und/oder Windkraftanlagen garantieren zu können. Da konventionelle Speichertechnologien wie beispielsweise Pumpspeicherkraftwerke durch fehlende mögliche Standorte in Deutschland nicht weiter ausgebaut werden, sind Alternativen notwendig. Es ist Konsens, hierfür emissionsarme Strategien zu entwickeln, um die gesetzten Ziele zur Reduktion von CO2 Emissionen zu erreichen. Neben Batterien, die vorzugsweise für Kurzzeitspeicher einzusetzen sind, bietet sich Wasserstoff als umweltfreundlicher Sekundärenergieträger an, der in großen Mengen gespeichert und in Brennstoffzellen mit hohem Wirkungsgrad emissionsfrei in elektrische Energie umgewandelt werden kann. Da elementarer Wasserstoff nicht natürlich vorkommt, ist dieser zuvor zu generieren. Überschüsse aus regenerativen Energiequellen können hierfür ideal genutzt werden. In diesem Beitrag wird ein aussichtsreiches Konzept für einen modularen Hochdruckelektrolyseur vorgestellt, welcher erlaubt, Wasserstoff bei einem hohen Ausgangsdruck bereitzustellen. Durch den prinzipiellen Aufbau, ist ein beliebiges Druckniveau am Ausgang nur von der mechanischen Stabilität der verwendeten Bauteile abhängig. Hierdurch ist es möglich, Wasserstoff direkt in einen Druckgasspeicher oder eine Pipeline zu produzieren, ohne einen zusätzlichen Verdichter nutzen zu müssen. Dies resultiert in signifikanten Kosteneinsparungen und verbessert den Systemwirkungsgrad zukünftiger Anlagen entscheidend. Y1 - 2015 SN - 978-3-86488-093-3 SP - 99 EP - 109 PB - vwh, Verlag Werner Hülsbusch, Fachverlag für Medientechnik und -wirtschaft CY - Glückstadt ER - TY - CHAP A1 - Sagewka, Christoph A1 - Rost, Ulrich A1 - Roth, Jeffrey A1 - Brodmann, Michael ED - Großmann, Uwe ED - Kunold, Ingo ED - Engels, Christoph T1 - Entwicklung von vollmodularen PEM-Brennstoffzellen- und Elektrolyseursystemen mit segmentierten, planaren Polplatten T2 - Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015 N2 - Im Rahmen der Energiewende ist eine Erweiterung der in das Verbund-netz integrierten Energiespeicher notwendig, um zukünftig die heute gewohnte Versorgungssicherheit trotz eines sehr hohen Anteils volatiler regenerativer Energieerzeugungsanlagen zu ermöglichen. Eine geeignete elektrochemische Methode zur umweltfreundlichen Zwischenspeicherung großer Energiemengen stellt die Wasserelektrolyse mit bedarfsorientierter Rückverstromung dar. Dabei können die dynamischen Einspeise- und Laständerungen im elektrischen Verbundnetz im besonderen Maße von Elektrolyseur- und Brennstoffzellen-systemen auf Basis von Polymer-Elektrolyt-Membranen (PEM) aufgefangen werden. Bestehende PEM-Systeme sind vor allem in ihrer konstruktiven Zellgröße und ihrer maximalen Leistung bei der Wasserstoffproduktion bzw. der Stromerzeugung stark begrenzt. Vor allem inhomogene Verpressungen großflächiger planarer Zellen in einem klassischen, mechanisch verspannten Stack führen zu hohen Leistungseinbußen. Zudem ergeben sich bei kleinen Stacks aufgrund der geringen Zellspannung ungünstige Wandlungsverhältnisse zwischen Strom und Spannung für eine vor- bzw. nachgeschaltete Leistungselektronik. Ein neuartiges Stackkonzept mit segmentierten Polplatten bietet eine konstruktive Lösung für das Problem größerer aktiver Zellflächen und leistet einen Beitrag zur Entwicklung industriell einsetzbarer Hochdruckelektrolyseure und Brennstoffzellen. Y1 - 2015 SN - 978-3-86488-093-3 SP - 115 EP - 121 PB - vwh, Verlag Werner Hülsbusch, Fachverlag für Medientechnik und -wirtschaft CY - Glückstadt ER - TY - CHAP A1 - Rost, Ulrich A1 - Roth, Jeffrey A1 - Brodmann, Michael ED - Kubis, Andreas ED - Rehtanz, Christian ED - Shapovalov, Anton ED - Hilbrich, Dominik ED - Plota, Ewa T1 - Modular Polymer Electrolyte Membrane Fuel Cell and Electrolyser Stack Design with Hydraulic Compression T2 - Power and Energy Student Summit(PESS) 2015, January 13th-14th, Dortmund Germany N2 - An energy economy with high share of renewable but volatile energy sources is dependent on storage strategies in order to ensure sufficient energy delivery in periods of e.g. low wind and/or low solar radiation. Hydrogen as environmental friendly energy carrier is thought to be an appropriate solution for large scale energy storage. In 2011 the NOW (national organisation for hydrogen in Germany) calculated the demand for hydrogen energy systems as positive (0.8 GW to 5.25 GW) and negative supply for varying power demand (0.68 to 4.3 GW) for the German energy economy in 2025. Due to its dynamic behaviour on load changes polymer electrolyte membrane fuel cells (PEMFC) as well as water electrolyser systems (PEMEL) can play a significant role for large scale hydrogen based storage systems. In this work a novel design concept for modular fuel cell and electrolyser stacks is presented with single cells in pockets surrounded by a hydraulic medium. This hydraulic medium introduces necessary compression forces on the membrane electrode assembly (MEA) of each cell within a stack. Furthermore, ideal stack cooling is achieved by this medium. Due to its modularity and scalability the modular stack design with hydraulic compression meets the requirements for large PEMFC as well as PEMEL units. Small scale prototypes presented in this work illustrate the potential of this design concept. Y1 - 2015 U6 - https://doi.org/10.17877/DE290R-7265 SP - S02.4 ER - TY - CHAP A1 - Brodmann, Michael A1 - Rost, Ulrich T1 - A Modular Stack Technology for Electrochemical Cells Based on Hydraulic Compression T2 - Konferenz: OZ-14, 7th German-Japanese Symposium on nanostructures, March 2-4, 2014 in Wenden/Olpe, Germany N2 - Membrane electrode assemblies (MEA) developed at the Westphalian Energy Institute for polymer electrolyte membrane fuel cells (PEMFC) are high tech systems containing various materials structured in nanoscale, at which electrochemical reactions occur on catalyst nano particle surfaces. For low reactance homogeneous compression of the MEA’s layers is necessary. A novel stack architecture for electrochemical cells, especially PEMFC as well as PEM electrolysers, has been developed according to achieve ideal cell operation conditions. Single cells of such a stack are inserted into flexible slots that are surrounded by hydraulic media. While operation the hydraulic media is pressurised which leads to an even compression and cooling of the stack’s cells. With this stack design it has been possible to construct a test facility for simultaneous characterisation of several MEA samples. As compression and temperature conditions of every single sample are equal, with the novel test system the effect of e.g. different electrode configurations can be investigated. Furthermore, the modular stack design leads to the development of hybrid energy applications combining fuel cells, electrolysers, batteries as well as metal hydride tanks in one system. Y1 - 2014 ER - TY - CHAP A1 - Wirkert, Florian Josef A1 - Roth, Jeffrey A1 - Rost, Ulrich A1 - Brodmann, Michael ED - Schulz, Detlef T1 - A novel PEM electrolysis system with dynamic hydraulic compression for an optimized high-pressure operation T2 - NEIS Conference 2016. Nachhaltige Energieversorgung und Integration von Speichern N2 - In this experimental work we present a novel electrolyzer system for the production of hydrogen and oxygen at high pressure levels without an additional mechanical compressor. Due to its control strategies, the operation conditions for this electrolyzer can be kept optimal for each load situation of the system. Furthermore, the novel system design allows for dynamic long-term operation as well as for easy maintainability. Therefore, the device meets the requirements for prospective power-to-gas applications, especially, in order to store excess energy from renewable sources. A laboratory scale device has been developed and high-pressure operation was validated. We also studied the long-term stability of the system by applying dynamic load cycles with load changes every 30 sec. After 80 h of operation the used membrane electrode assembly (MEA) was investigated by means of SEM, EDX and XRD analysis. KW - PEM Electrolysis KW - Hydrogen KW - Hydraulic Compression KW - High Pressure Y1 - 2016 SN - 978-3-658-15028-0 SP - 169 EP - 174 PB - Springer Vieweg CY - Wiesbaden ET - 1 ER - TY - CHAP A1 - Mutascu, Cristian A1 - Rost, Ulrich A1 - Brodmann, Michael ED - Großmann, Uwe ED - Kunold, Ingo ED - Engels, Christoph T1 - GeoFuelCells - Energieautarke Bohrlochsensorik mittels Brennstoffzellen T2 - Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015 N2 - Im Rahmen eines gemeinsamen Forschungsprojekts mit dem Titel „Energieautarke Bohrlochsensorik mittels Brennstoffzellen – GeoFuelCells“ wurde vom Geothermie-Zentrum Bochum und dem Westfälischen Energieinstitut, unterstützt aus dem Förderprogramm Ziel 2 (2007-2013 EFRE) des Landes NRW, ein brennstoffzellenbasiertes Energieversorgungssystem für Bohrloch-Anwendungen entwickelt. Y1 - 2015 SN - 978-3-86488-093-3 SP - 109 EP - 115 PB - vwh, Verlag Werner Hülsbusch, Fachverlag für Medientechnik und -wirtschaft CY - Glückstadt ER - TY - CHAP A1 - Brodmann, Michael A1 - Rost, Ulrich T1 - Batterien, Brennstoffzellen, Elektrolyseure – Forschung und Entwicklung an der Westfälischen Hochschule T2 - Konferenz: Batterietag NRW 2017, 28. März 2017 in Aachen Y1 - 2017 N1 - Die vorgestellte Präsentation ist auf der Konferenz-Homepage als Download für die Teilnehmer veröffentlicht worden ER - TY - CHAP A1 - Rost, Ulrich A1 - Marginean, Gabriela A1 - Muntean, Roxana A1 - Podleschny, Pit Yannick A1 - Brodmann, Michael A1 - Merino, Cesar A1 - Diez, Roberto ED - International Energy and Sustainability Conference , T1 - A cost-effective PEM fuel cell test system based on hydraulic compression with optimized platinum catalyst loading T2 - International Energy and Sustainability Conference (IESC), June 30 - July 1, 2016 N2 - 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. KW - Hydraulic compression KW - Carbon Nano Fibers KW - PEM Fuel Cells KW - Catalyst utilization Y1 - 2016 SN - 978-1-5090-2980-8 U6 - https://doi.org/10.1109/IESC.2016.7569500 PB - IEEE CY - [Piscataway, NJ] ER - TY - JOUR A1 - Rost, Ulrich A1 - Muntean, Roxana A1 - Podleschny, Pit Yannick A1 - Marginean, Gabriela A1 - Brodmann, Michael A1 - Şerban, Viorel-Aurel T1 - Influence of the Graphitisation Degree of Carbon Nano Fibres Serving as Support Material for Noble Metal Electro Catalysts on the Performance of PEM Fuel Cells JF - Solid state phenomena N2 - In this experimental work polymer electrolyte membrane fuel cell (PEMFC) electrodes are analysed, which are prepared by the use of two sorts of carbon nano fibres (CNF) serving as support material for platinum nano particles. Those CNFs, which are heat treated subsequently to their production, have a higher graphitisation degree than fibres as produced. The improved graphitisation degree leads to higher electrical conductivity, which is favourably for the use in PEMFC electrodes. Samples have been analysed, in order to determine graphitisation degree, electrical conductivity, as well as morphology and loading of the prepared electro catalyst. Membrane electrode assemblies manufactured from prepared electrodes are analysed in-situ in a PEM fuel cell test environment. It has been determined that power output for samples containing CNFs with higher graphitisation degree is increased by about 13.5%. Y1 - 2016 U6 - https://doi.org/10.4028/www.scientific.net/SSP.254.27 IS - 254 SP - 27 EP - 32 ER - TY - CHAP A1 - Muntean, Roxana A1 - Pascal, Dragos-Toader A1 - Rost, Ulrich A1 - Podleschny, Pit Yannick A1 - Marginean, Gabriela A1 - Schumacher, Marc T1 - Studies on pulse electrodeposition of Pt-Ni binary alloy for electrochemical cell applications, 7th International Symposium on Advanced Materials and Structures T2 - Konferenz: 7th International Conference on Advanced Materials and Structures (AMS 2018), 28.-31. März 2018 in Timisoara (Rumänien) Y1 - 2018 ER - TY - JOUR A1 - Muntean, Roxana A1 - Rost, Ulrich A1 - Marginean, Gabriela A1 - Vaszilcsin, Nicolae T1 - Optimisation of the Electrodeposition Parameters for Platinum Nanoparticles on Carbon Nanofibers Support JF - Solid state phenomena N2 - 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 KW - carbon nanofibers KW - platinum electrodeposition KW - electrocatalysts Y1 - 2016 U6 - https://doi.org/10.4028/www.scientific.net/SSP.254.153 IS - 254 SP - 153 EP - 158 ER - TY - JOUR A1 - Muntean, Roxana A1 - Rost, Ulrich A1 - Pascal, Dragos-Toader A1 - Marginean, Gabriela A1 - Vaszilcsin, Nicolae T1 - Determination of the Electrochemical Surface Area for CNF-Pt Electrocatalyst Using Cyclic Voltammetry JF - Chemical Bulletin of “Politehnica” University of Timisoara, Romania N2 - 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. KW - carbon nanofibers KW - platinum electrodeposition KW - electrochemical surface area Y1 - 2016 VL - 61 (75) IS - 2 SP - 44 EP - 48 ER - TY - CHAP A1 - Rost, Ulrich A1 - Brodmann, Michael A1 - Zekorn, Bruno A1 - Peinecke, Volker A1 - Radev, Ivan A1 - Podleschny, Pit Yannick T1 - PEM fuel cell electrode preparation using oxygen plasma treated graphene related material serving as catalyst support for platinum nanoparticles T2 - Konferenz: 7. NRW Nano-Konferenz, 7.-8. Dezember 2016 in Münster N2 - 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. KW - PEM fuel cells KW - electrode preparation KW - carbon nanofibers KW - in-situ performance test Y1 - 2016 N1 - Die orale Präsentation auf der NMWP Young Academics in Siegen (30.-31. August) von Muntean, R.; Rost, U.; Brodmann, M. (2016): PEM Fuel Cells Electrodes Preparation Using Oxygen Plasma Treated Graphene Related Material Serving as Catalyst Support for Platinum Nanoparticles hatte die Einladung zur 7. NRW Nanokonferenz (7.-8. Dezember) mit einem Poster und einem Paper zur Folge. Dabei war die Vorgabe, dass sich der Titel nicht ändern durfte. ER - TY - CHAP A1 - Rost, Ulrich A1 - Rigou, Veronica A1 - Marginean, Gabriela A1 - Brodmann, Michael A1 - Brandl, Waltraut T1 - Oxygen Plasma Activated Carbon Nanofibres as Electrode Material for Proton Exchange Membrane Fuel Cells T2 - Konferenz: Junior Euromat 2014: The Major Event for Young Materials Scientists, 21.-25. Juli 2014 in Lausanne (Schweiz) N2 - To further increase platinum utilisation in PEM fuel cells CNFs are investigated as catalyst support material due to the CNF’s high specific surface area. Furthermore, CNFs provide suitable properties concerning corrosion resistance as well as electrical conductivity in contrast to conventional carbon supports. This work presents the results of an electrode preparation procedure based on O2 plasma activated CNFs. The plasma treatment leads to CNF dispersibility in alcohol/water for a spray coating process. Furthermore, O2 plasma activation enhances metal deposition on the CNF’s surface. Pulse plating procedure as well as wet chemical metal synthesis have been used for particle deposition. For pulse plating a potentiostat/galvanostat type MMates 510 AC from Materials Mates, Italy has been used. Electrode morphology has been determined in SEM type XL 30 ESEM from Philips, The Netherlands. Y1 - 2014 ER - TY - JOUR A1 - Muntean, Roxana A1 - Pascal, Dragos-Toader A1 - Rost, Ulrich A1 - Holtkotte, Lisa A1 - Näther, Johannes A1 - Köster, Frank A1 - Underberg, Martin A1 - Hülser, Tim A1 - Brodmann, Michael T1 - Investigation of Iridium Nanoparticles Supported on Sub-stoichiometric Titanium Oxides as Anodic Electrocatalysts in PEM Electrolysis. Part I.: Synthesis and Characterization JF - Topics in Catalysis Y1 - 2019 U6 - https://doi.org/10.1007/s11244-019-01164-3 SN - 1022-5528 VL - 62 IS - 5-6 SP - 429 EP - 438 ER -