@article{RostBrodmannZekornetal., 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 = {Materials today. Proceedings}, volume = {4}, journal = {Materials today. Proceedings}, number = {Supplement 2}, issn = {2214-7853}, doi = {10.1016/j.matpr.2017.09.195}, pages = {S249 -- S252}, abstract = {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.}, language = {en} } @article{RostMunteanMargineanetal.2016, author = {Rost, Ulrich and Muntean, Roxana and Marginean, Gabriela and Merino, Cesar and Diez, Roberto and Vaszilcsin, Nicolae and Brodmann, Michael}, title = {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}, series = {International Journal of Electrochemical Science}, volume = {2016}, journal = {International Journal of Electrochemical Science}, number = {Volume 11, Issue 11}, publisher = {Elsevier}, issn = {1452-3981}, doi = {10.20964/2016.11.55}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-9509}, pages = {9110 -- 9122}, year = {2016}, abstract = {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.}, language = {en} } @article{KazamerTackSpreeetal.2025, author = {Kazamer, Norbert and Tack, Meike and Spree, Mathias and Underberg, Martin and Rost, Ulrich and Reichenberger, Sven and Cieluch, Maximilian and Salih, Haujin and Wirkert, Florian Josef and B{\"o}hm, Leonard and Roth, Jeffrey and Nallathambi, Varatharaja and Gault, Baptiste and Baer, Christoph and Orend, Kerstin and Barcikowski, Stephan and H{\"u}lser, Tim and Brodmann, Michael}, title = {Ultrasonically Deposited Boron-Doped Silicon Decorated with Laser-Generated Iridium Nanoparticles as Manufacturing Approach for OER Electrodes in PEM Water Electrolysis}, series = {Advanced Materials Interfaces}, volume = {2025}, journal = {Advanced Materials Interfaces}, number = {Volume 12, Issue 8}, publisher = {Wiley}, doi = {10.1002/admi.202400765}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:1010-opus4-46883}, pages = {13}, year = {2025}, abstract = {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.}, language = {en} } @article{WirkertRothRostetal.2017, author = {Wirkert, Florian Josef and Roth, Jeffrey and Rost, Ulrich and Brodmann, Michael}, title = {Hydraulic cell compression for performance preserving upscaling of PEM electrolyzers}, series = {International Journal of Smart Grid and Clean Energy}, volume = {6}, journal = {International Journal of Smart Grid and Clean Energy}, number = {3}, issn = {2315-4462}, doi = {10.12720/sgce.6.3.171-176}, pages = {171 -- 176}, year = {2017}, abstract = {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.}, language = {en} } @inproceedings{PodleschnyMunteanRostetal.2016, author = {Podleschny, Pit Yannick and Muntean, Roxana and Rost, Ulrich and Brodmann, Michael}, title = {PEM Fuel Cells Electrodes Preparation Using Oxygen Plasma Treated Graphene Related Material Serving as Catalyst Support for Platinum Nanoparticles}, series = {Konferenz: NMWP Young Academics: Graphen und 2D-Materialien, 30.-31. August 2016 in Siegen}, booktitle = {Konferenz: NMWP Young Academics: Graphen und 2D-Materialien, 30.-31. August 2016 in Siegen}, 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 = {en} } @inproceedings{RostRothBrodmann2015, author = {Rost, Ulrich and Roth, Jeffrey and Brodmann, Michael}, title = {Ein neuartiges Konzept f{\"u}r Hochdruckelektrolyseursysteme in modularer Bauweise zur Produktion von Wasserstoff aus {\"U}berschussenergie erneuerbarer Quellen}, series = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, booktitle = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, editor = {Großmann, Uwe and Kunold, Ingo and Engels, Christoph}, publisher = {vwh, Verlag Werner H{\"u}lsbusch, Fachverlag f{\"u}r Medientechnik und -wirtschaft}, address = {Gl{\"u}ckstadt}, isbn = {978-3-86488-093-3}, pages = {99 -- 109}, year = {2015}, abstract = {F{\"u}r einen Energiesektor, der zuk{\"u}nftig 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 k{\"o}nnen. Da konventionelle Speichertechnologien wie beispielsweise Pumpspeicherkraftwerke durch fehlende m{\"o}gliche Standorte in Deutschland nicht weiter ausgebaut werden, sind Alternativen notwendig. Es ist Konsens, hierf{\"u}r emissionsarme Strategien zu entwickeln, um die gesetzten Ziele zur Reduktion von CO2 Emissionen zu erreichen. Neben Batterien, die vorzugsweise f{\"u}r Kurzzeitspeicher einzusetzen sind, bietet sich Wasserstoff als umweltfreundlicher Sekund{\"a}renergietr{\"a}ger an, der in großen Mengen gespeichert und in Brennstoffzellen mit hohem Wirkungsgrad emissionsfrei in elektrische Energie umgewandelt werden kann. Da elementarer Wasserstoff nicht nat{\"u}rlich vorkommt, ist dieser zuvor zu generieren. {\"U}bersch{\"u}sse aus regenerativen Energiequellen k{\"o}nnen hierf{\"u}r ideal genutzt werden. In diesem Beitrag wird ein aussichtsreiches Konzept f{\"u}r 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 Stabilit{\"a}t der verwendeten Bauteile abh{\"a}ngig. Hierdurch ist es m{\"o}glich, Wasserstoff direkt in einen Druckgasspeicher oder eine Pipeline zu produzieren, ohne einen zus{\"a}tzlichen Verdichter nutzen zu m{\"u}ssen. Dies resultiert in signifikanten Kosteneinsparungen und verbessert den Systemwirkungsgrad zuk{\"u}nftiger Anlagen entscheidend.}, language = {de} } @inproceedings{SagewkaRostRothetal.2015, author = {Sagewka, Christoph and Rost, Ulrich and Roth, Jeffrey and Brodmann, Michael}, title = {Entwicklung von vollmodularen PEM-Brennstoffzellen- und Elektrolyseursystemen mit segmentierten, planaren Polplatten}, series = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, booktitle = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, editor = {Großmann, Uwe and Kunold, Ingo and Engels, Christoph}, publisher = {vwh, Verlag Werner H{\"u}lsbusch, Fachverlag f{\"u}r Medientechnik und -wirtschaft}, address = {Gl{\"u}ckstadt}, isbn = {978-3-86488-093-3}, pages = {115 -- 121}, year = {2015}, abstract = {Im Rahmen der Energiewende ist eine Erweiterung der in das Verbund-netz integrierten Energiespeicher notwendig, um zuk{\"u}nftig die heute gewohnte Versorgungssicherheit trotz eines sehr hohen Anteils volatiler regenerativer Energieerzeugungsanlagen zu erm{\"o}glichen. Eine geeignete elektrochemische Methode zur umweltfreundlichen Zwischenspeicherung großer Energiemengen stellt die Wasserelektrolyse mit bedarfsorientierter R{\"u}ckverstromung dar. Dabei k{\"o}nnen die dynamischen Einspeise- und Last{\"a}nderungen 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 Zellgr{\"o}ße und ihrer maximalen Leistung bei der Wasserstoffproduktion bzw. der Stromerzeugung stark begrenzt. Vor allem inhomogene Verpressungen großfl{\"a}chiger planarer Zellen in einem klassischen, mechanisch verspannten Stack f{\"u}hren zu hohen Leistungseinbußen. Zudem ergeben sich bei kleinen Stacks aufgrund der geringen Zellspannung ung{\"u}nstige Wandlungsverh{\"a}ltnisse zwischen Strom und Spannung f{\"u}r eine vor- bzw. nachgeschaltete Leistungselektronik. Ein neuartiges Stackkonzept mit segmentierten Polplatten bietet eine konstruktive L{\"o}sung f{\"u}r das Problem gr{\"o}ßerer aktiver Zellfl{\"a}chen und leistet einen Beitrag zur Entwicklung industriell einsetzbarer Hochdruckelektrolyseure und Brennstoffzellen.}, language = {de} } @inproceedings{RostRothBrodmann2015, author = {Rost, Ulrich and Roth, Jeffrey and Brodmann, Michael}, title = {Modular Polymer Electrolyte Membrane Fuel Cell and Electrolyser Stack Design with Hydraulic Compression}, series = {Power and Energy Student Summit(PESS) 2015, January 13th-14th, Dortmund Germany}, booktitle = {Power and Energy Student Summit(PESS) 2015, January 13th-14th, Dortmund Germany}, editor = {Kubis, Andreas and Rehtanz, Christian and Shapovalov, Anton and Hilbrich, Dominik and Plota, Ewa}, doi = {10.17877/DE290R-7265}, pages = {S02.4}, year = {2015}, abstract = {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.}, language = {en} } @inproceedings{BrodmannRost2014, author = {Brodmann, Michael and Rost, Ulrich}, title = {A Modular Stack Technology for Electrochemical Cells Based on Hydraulic Compression}, series = {Konferenz: OZ-14, 7th German-Japanese Symposium on nanostructures, March 2-4, 2014 in Wenden/Olpe, Germany}, booktitle = {Konferenz: OZ-14, 7th German-Japanese Symposium on nanostructures, March 2-4, 2014 in Wenden/Olpe, Germany}, year = {2014}, abstract = {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.}, language = {en} } @inproceedings{WirkertRothRostetal.2016, author = {Wirkert, Florian Josef and Roth, Jeffrey and Rost, Ulrich and Brodmann, Michael}, title = {A novel PEM electrolysis system with dynamic hydraulic compression for an optimized high-pressure operation}, series = {NEIS Conference 2016. Nachhaltige Energieversorgung und Integration von Speichern}, booktitle = {NEIS Conference 2016. Nachhaltige Energieversorgung und Integration von Speichern}, editor = {Schulz, Detlef}, edition = {1}, publisher = {Springer Vieweg}, address = {Wiesbaden}, isbn = {978-3-658-15028-0}, pages = {169 -- 174}, year = {2016}, abstract = {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.}, language = {en} } @inproceedings{MutascuRostBrodmann2015, author = {Mutascu, Cristian and Rost, Ulrich and Brodmann, Michael}, title = {GeoFuelCells - Energieautarke Bohrlochsensorik mittels Brennstoffzellen}, series = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, booktitle = {Energiewende regional - Trends, Treiber, Allianzen. Smart Energy 2015}, editor = {Großmann, Uwe and Kunold, Ingo and Engels, Christoph}, publisher = {vwh, Verlag Werner H{\"u}lsbusch, Fachverlag f{\"u}r Medientechnik und -wirtschaft}, address = {Gl{\"u}ckstadt}, isbn = {978-3-86488-093-3}, pages = {109 -- 115}, year = {2015}, abstract = {Im Rahmen eines gemeinsamen Forschungsprojekts mit dem Titel „Energieautarke Bohrlochsensorik mittels Brennstoffzellen - GeoFuelCells" wurde vom Geothermie-Zentrum Bochum und dem Westf{\"a}lischen Energieinstitut, unterst{\"u}tzt aus dem F{\"o}rderprogramm Ziel 2 (2007-2013 EFRE) des Landes NRW, ein brennstoffzellenbasiertes Energieversorgungssystem f{\"u}r Bohrloch-Anwendungen entwickelt.}, language = {de} } @inproceedings{BrodmannRost2017, author = {Brodmann, Michael and Rost, Ulrich}, title = {Batterien, Brennstoffzellen, Elektrolyseure - Forschung und Entwicklung an der Westf{\"a}lischen Hochschule}, series = {Konferenz: Batterietag NRW 2017, 28. M{\"a}rz 2017 in Aachen}, booktitle = {Konferenz: Batterietag NRW 2017, 28. M{\"a}rz 2017 in Aachen}, year = {2017}, language = {de} } @inproceedings{RostMargineanMunteanetal.2016, author = {Rost, Ulrich and Marginean, Gabriela and Muntean, Roxana and Podleschny, Pit Yannick and Brodmann, Michael and Merino, Cesar and Diez, Roberto}, title = {A cost-effective PEM fuel cell test system based on hydraulic compression with optimized platinum catalyst loading}, series = {International Energy and Sustainability Conference (IESC), June 30 - July 1, 2016}, booktitle = {International Energy and Sustainability Conference (IESC), June 30 - July 1, 2016}, editor = {International Energy and Sustainability Conference ,}, publisher = {IEEE}, address = {[Piscataway, NJ]}, isbn = {978-1-5090-2980-8}, doi = {10.1109/IESC.2016.7569500}, pages = {6}, year = {2016}, abstract = {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.}, language = {en} } @article{RostMunteanPodleschnyetal.2016, author = {Rost, Ulrich and Muntean, Roxana and Podleschny, Pit Yannick and Marginean, Gabriela and Brodmann, Michael and Şerban, Viorel-Aurel}, title = {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}, series = {Solid state phenomena}, journal = {Solid state phenomena}, number = {254}, doi = {10.4028/www.scientific.net/SSP.254.27}, pages = {27 -- 32}, year = {2016}, abstract = {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\%.}, language = {en} } @inproceedings{MunteanPascalRostetal.2018, author = {Muntean, Roxana and Pascal, Dragos-Toader and Rost, Ulrich and Podleschny, Pit Yannick and Marginean, Gabriela and Schumacher, Marc}, title = {Studies on pulse electrodeposition of Pt-Ni binary alloy for electrochemical cell applications, 7th International Symposium on Advanced Materials and Structures}, series = {Konferenz: 7th International Conference on Advanced Materials and Structures (AMS 2018), 28.-31. M{\"a}rz 2018 in Timisoara (Rum{\"a}nien)}, booktitle = {Konferenz: 7th International Conference on Advanced Materials and Structures (AMS 2018), 28.-31. M{\"a}rz 2018 in Timisoara (Rum{\"a}nien)}, year = {2018}, 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} } @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} } @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} } @inproceedings{RostRigouMargineanetal.2014, author = {Rost, Ulrich and Rigou, Veronica and Marginean, Gabriela and Brodmann, Michael and Brandl, Waltraut}, title = {Oxygen Plasma Activated Carbon Nanofibres as Electrode Material for Proton Exchange Membrane Fuel Cells}, series = {Konferenz: Junior Euromat 2014: The Major Event for Young Materials Scientists, 21.-25. Juli 2014 in Lausanne (Schweiz)}, booktitle = {Konferenz: Junior Euromat 2014: The Major Event for Young Materials Scientists, 21.-25. Juli 2014 in Lausanne (Schweiz)}, pages = {1}, year = {2014}, abstract = {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.}, language = {en} } @article{MunteanPascalRostetal.2019, author = {Muntean, Roxana and Pascal, Dragos-Toader and Rost, Ulrich and Holtkotte, Lisa and N{\"a}ther, Johannes and K{\"o}ster, Frank and Underberg, Martin and H{\"u}lser, Tim and Brodmann, Michael}, title = {Investigation of Iridium Nanoparticles Supported on Sub-stoichiometric Titanium Oxides as Anodic Electrocatalysts in PEM Electrolysis. Part I.: Synthesis and Characterization}, series = {Topics in Catalysis}, volume = {62}, journal = {Topics in Catalysis}, number = {5-6}, issn = {1022-5528}, doi = {10.1007/s11244-019-01164-3}, pages = {429 -- 438}, year = {2019}, language = {en} }