Download or read book Study of an Iron nitrogen graphene Catalyst for Polymer Electrolyte Membrane Fuel Cells written by Pierre Pascone and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The work of this thesis is in the field of non-noble metal catalysts for the oxygen reduction reaction (ORR) of a polymer electrolyte membrane fuel cell (PEMFC). The ORR requires a catalyst, platinum providing presently the highest level of catalytic activity and being used in essentially all PEMFC applications. Platinum is however a very expensive metal that has hindered the large scale production of PEMFCs in everyday products, generating a desire to develop a low-cost alternative. In this thesis, the proposed catalyst is composed of iron coming from a salt and a carbon nanomaterial with nitrogen functionalities, with one important goal being to improve the time stability of such iron-based catalyst materials. The carbon nanomaterial used is stacked graphene structures having 5 - 20 atomic layers, referred to as graphene nanoflakes (GNFs). The GNFs were produced in-house through gas phase homogeneous nucleation following the plasma decomposition of a carbon-containing feedstock in an inductively coupled plasma torch reactor. By introducing nitrogen gas, either directly during GNF structural growth or in a second treatment step following growth, nitrogen functional groups are bonded to the surface and edges of graphene in different amounts. Iron acetate was used as the source of iron and added to the GNF structures before being heat-treated to generate the final ORR catalysts. Another recipe for producing the catalyst included phenanthroline as an added nitrogen source. An electrochemical study performed in neutral media was used as a screening technique to determine the effect of nitrogen functionalization on the GNF support system and its interaction with phenanthroline in producing an active catalyst. The best candidate proved to be the catalyst derived from using GNFs with high levels (15 - 20 atomic percent on the surface) of nitrogen, further referred to as high-nitrogen GNFs (HN-GNFs), and without phenanthroline added. This modified synthesis recipe was used for the duration of the thesis. The catalyst`s surface was also characterized with x-ray photoelectron spectroscopy and imaged with electron microscopy. Catalysts with three different iron concentrations were then synthesized and put through another electrochemical study to investigate the effect of the iron weight percent on the catalyst in different media (acidic, neutral, basic). The catalysts performed well in acidic media, which is vital for a PEMFC catalyst; this result indicated that PEMFC testing should proceed. Additionally, having more iron present allowed a characterization study to be carried out to explore what the shape, location, and bonding of the iron nanoparticles were. It was seen that the majority of the iron is in the form of nanoparticles and are not found on the surface, but encapsulated by the graphene sheets of the HN-GNFs.The best materials produced throughout the thesis and evaluated through the electrochemical study were tested in a single-cell PEMFC as the ORR catalyst. Although the current density being drawn from the cell was low when compared to other iron-containing catalysts being developed in other research groups around the world, the catalyst developed effectively showed good stability over the 200 hours of testing." --

Download or read book Nanostructured Non precious Metal Catalyst and Its Behavior in the Catalyst Layer in PEM Fuel Cells written by Ja-Yeon Choi and published by . This book was released on 2017 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer electrolyte membrane (PEM) fuel cells have been viewed as promising power source candidates for transport, stationary, and portable applications due to their high efficiency and low emissions. The platinum is the most commonly used catalyst material for the oxygen reduction reaction (ORR) at the cathode of PEM fuel cells; however, the limited abundance and high cost of platinum hinder the large-scale commercialization of fuel cells. Two approaches being widely accepted to overcome this limitation are 1) to improve Pt utilization to boost the activity while reducing the loading, or 2) to develop non-precious metal catalysts (NPMCs) with sufficient activity and stability to be used in the PEM fuel cells. Despite the ample amount of research and improvements, the activity and stability of these NPMCs must be further improved to be practical in PEMFC applications. The activity can be further enhanced by several different approaches including but not limited to: 1) use of different dopants (nitrogen, boron, sulfur, etc.) precursors, 2) use of different non-platinum group metals (Fe, Co, Mn), 3) utilizing high surface area support materials and 4) applying heat treatment in various conditions. The combination of these approaches affect the active site density and distribution, electronic structure of the active site thus affecting its kinetics and turn over frequency, electrical conductivity and stability of the catalyst in various ways. Herein, two chapters are included exploring with the above mentioned combinations to synthesize highly active and stable catalysts, followed by another chapter investigating its fuel cell performance and discussing possible causes of stability loss with a method to verify the issue with flooding of the microporous active sites. In the first study, non-precious metal oxygen reduction reaction (ORR) catalysts were prepared by pyrolyzing a carbon supported complex consisting of iron acetate coordinated with 1,2,4,5-tetracyanobenzene (TCNB) in an iron phtalocyanine-like polymer arrangement. By employing these small precusursor molecules, it is expected that more uniform and complete coverage of the carbon support material can be obtained, and by using the in situ formation and polymerization of FePc, effective iron-center segregation can be achieved. The results suggest that this type of catalyst has great potential used as a non-precious PEM fuel cell catalyst. In the second study, Co-N decorated porous graphene aerogel catalyst was synthesized as an efficient catalyst for ORR. In the preparation process, polyaniline (PANI) is introduced as a pore-forming agent to aid in the self-assemble of graphene species into a porous aerogel networks, and a nitrogen precursor to induce in situ nitrogen doping. Such highly desired structures can not only expose sufficient active sites for the ORR but also guarantee the fast mass transfer in the catalytic process, which provides significant catalytic activity with positive onset and half wave potentials, low hydrogen peroxide yield and remarkable stability in acid medium. In the last chapter, with a highly microporous catalyst made with dual nitrogen precursors (phenanthroline and polyaniline), a systematic study is performed to investigate micropore flooding in-situ before and after stability testing. The results do not support micropore flooding as being a large contributor to instability, at least for the family of NPMCs evaluated in this work. The protocol outlined here can be used by other researchers in the NPMC community to diagnose micropore flooding in their own respective catalysts. Several recommendations for future work were suggested in the last section of this work to further apply the knowledge to design a highly active, durable, and low-cost NPMCs.

Download or read book Synthesis Characterization and Performance of Graphene Nanoflakes as a Non noble Metal Catalyst in Polymer Electrolyte Membrane Fuel Cells written by Pierre Pascone and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "One of the goals in catalyst research for proton exchange membrane fuel cells (PEMFCs) is to find a cost-efficient alternative to platinum. Due to sluggish kinetics, the major requirement of the platinum comes from the catalyst layer used for the oxygen reduction reaction (ORR). Functionalized carbon nanomaterials present themselves as good candidates for the replacement of platinum due to their low cost, excellent electrical conductivity, and chemical resistance to acidic and basic environments. In this work, graphene nanoflakes (GNFs), which are nanopowders consisting of stacked graphene sheets, were used to support atomic iron as a non-noble metal catalyst. In the first stage of the study the iron-based catalyst was synthesized. Synthesis steps include the production of GNFs in methane plasma, adsorption of ferric acetate, and pyrolysis in ammonia-rich atmosphere. The catalyst structure was characterized at various stages throughout the synthesis steps and it was found that 0.28 atomic percent of iron could successfully be incorporated onto the surface. However, the synthesis method employed caused a general decrease to all calculated crystallinity parameters: purity decreased by 28%, crystallite size decreased by a factor of 2, and the average length of graphene plane decreased by a factor of 4. Characterization was also performed on the catalyst layer after it had been exposed to the PEMFC environment, revealing that the crystallinity parameters actually improved with respect to exposure time: after 100 hours purity increased by 32%, crystallite size increased by 25%, and the average length of graphene plane increased by 107%. Exposure to the PEMFC environment repairs the damage done to the original GNFs during the synthesis steps. The synthesized catalyst was used in the catalyst layer for the ORR of a PEMFC with a 1 cm2 active surface. A current of 150 mA/cm2 was observed at an applied voltage of 0.5 Volts with a catalyst loading of 1 mg. When the current is normalized with respect to the amount of metal present, the result of 11.8 A/mg of metal catalyst from the present catalyst out-performs most platinum-based catalysts being used in industry; current platinum catalyst have values ranging from 3 to 14 A/mg of platinum. In stability experiments, no losses were observed at the end of 100-hours long experiments performed at an applied voltage of 0.5 Volts. This represents a great improvement over comparable iron-based catalysts, which show a 45% loss under identical test conditions. The increased stability of the catalyst support structure demonstrates the advantage of the high crystallinity and large crystalline lengths of the GNFs in comparison to other commercial carbon blacks." --

Download or read book Non Noble Metal Fuel Cell Catalysts written by Zhongwei Chen and published by John Wiley & Sons. This book was released on 2014-04-03 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written and edited by top fuel cell catalyst scientists and engineers from both industry and academia, this is the first book to provide a complete overview of this hot topic. It covers the synthesis, characterization, activity validation and modeling of different non-noble metal electrocatalysts, as well as their integration into fuel cells and their performance validation, while also discussing those factors that will drive fuel cell commercialization. With its well-structured approach, this is a must-have for researchers working on the topic, and an equally valuable companion for newcomers to the field.

Download or read book Study of a Platinum graphene Nanoflakes Catalyst for Oxygen Reduction Reaction of Polymer Electrolyte Membrane Fuel Cells written by Md Mahdi Feroze and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This master's thesis investigates the electrocatalytic performance of graphene nanoflakes (GNF) as the support of a noble catalyst towards oxygen reduction reaction (ORR) in acidic medium for application in polymer electrolyte membrane fuel cells (PEMFC). The graphene nanoflakes support is synthesized using methods developed by Pristavita et al. in 2011. Introducing platinum onto the support using thermal plasma is shown not possible in part due to limitations arising from the high boiling point of platinum. A wet chemistry technique developed by Jaoun et al. in 2003 is used to successfully introduce platinum onto the GNF support. The synthesized catalyst shows superior electrocatalytic activity towards ORR compared to a noble commercial catalyst having carbon black as supports, these tests being performed at high rotation speeds of rotating disk electrode (RDE) tests." --

Download or read book Development of Novel Nano structured Materials with Low cost and High Stability for PEM Fuel Cell written by Dongsheng Geng and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer electrolyte membrane fuel cells (PEMFCs) are non-polluting and efficient energy conversion devices that are expected to play a dominant role in energy solutions of the future. However, due to high cost and known degradation issue of Pt electrocatalyst, more durable, efficient, and inexpensive electrocatalysts are required before fuel cells can become commercially viable. This research is revolving around the development of electrocatalysts such as non-noble metal oxygen reduction reaction (ORR) catalyst, new alternative supports, and novel Pt nanostructures to address the above-mentioned challenges in PEMFCs. Firstly, we report the synthesis of nitrogen doped carbon nanotubes (CNx) and nitrogen doped graphene (N-graphene) with the various nitrogen contents. The relationship between structures and ORR activity is investigated in detail. We identified the real active site by the study. Most importantly, CNx and N-graphene have the comparable ORR activity even the improved durability compared with a platinum-based catalyst, showing the potential to replace costly Pt/C catalyst in alkaline fuel cells. Secondly, due to the advantages of N-graphene as not only a support of Pt but the non-noble metal ORR catalyst, we developed three different methods to prepare it: (i) post-treatment of graphene with ammonia (ii) from CNx to N-graphene directly (iii) one-step solvothermal process. Especially, by the solvothermal method, for the first time, nanoflower-like N-graphene was obtained with pure sp2 hybridized carbon and the controllable nitrogen types. Importantly, the synthesized materials exhibit much higher durability as Pt support for fuel cells than commercial carbon powder. Thirdly, previous results have shown that star-like Pt nanowires have both good catalytic activity and durability for ORR. However, there is a limitation in scale up and the controlling length and shape of Pt nanowire for previous method. Here we report a universal method to address the challenge. It is a very simple, green and efficient wet chemical route without any surfactant and template to produce urchin-shaped Pt nanostructures in high yield. In summary, the discoveries in this thesis contribute to development of fuel cell cathode electrocatalysts and make the improvement in electrocatalyst cost and stability.

Download or read book Polymer Electrolyte Fuel Cells 14 PEFC 14 written by H. Gasteiger and published by The Electrochemical Society. This book was released on 2014 with total page 1269 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book PEM Fuel Cells written by Yun Wang and published by Momentum Press. This book was released on 2013-04-06 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer Electrolyte Membrane (PEM) fuel cells convert chemical energy in hydrogen into electrical energy with water as the only by-product. Thus, PEM fuel cells hold great promise to reduce both pollutant emissions and dependency on fossil fuels, especially for transportation—passenger cars, utility vehicles, and buses—and small-scale stationary and portable power generators. But one of the greatest challenges to realizing the high efficiency and zero emissions potential of PEM fuel cells technology is heat and water management. This book provides an introduction to the essential concepts for effective thermal and water management in PEM fuel cells and an assessment on the current status of fundamental research in this field. The book offers you: • An overview of current energy and environmental challenges and their imperatives for the development of renewable energy resources, including discussion of the role of PEM fuel cells in addressing these issues; • Reviews of basic principles pertaining to PEM fuel cells, including thermodynamics, electrochemical reaction kinetics, flow, heat and mass transfer; and • Descriptions and discussions of water transport and management within a PEM fuel cell, including vapor- and liquid-phase water removal from the electrodes, the effects of two-phase flow, and solid water or ice dynamics and removal, particularly the specialized case of starting a PEM fuel cell at sub-freezing temperatures (cold start) and the various processes related to ice formation.

Download or read book Electrocatalysts for Fuel Cells and Hydrogen Evolution written by Abhijit Ray and published by BoD – Books on Demand. This book was released on 2018-12-05 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book starts with a theoretical understanding of electrocatalysis in the framework of density functional theory followed by a vivid review of oxygen reduction reactions. A special emphasis has been placed on electrocatalysts for a proton-exchange membrane-based fuel cell where graphene with noble metal dispersion plays a significant role in electron transfer at thermodynamically favourable conditions. The latter part of the book deals with two 2D materials with high economic viability and process ability and MoS2 and WS2 for their prospects in water-splitting from renewable energy.

Download or read book Advanced Non precious Metal Catalyst for Oxygen Reduction Reaction in Polymer Electrolyte Membrane Fuel Cells written by Gaopeng Jiang and published by . This book was released on 2018 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: To address the global energy and environmental challenges, the polymer electrolyte membrane fuel cell (PEMFC) is proposed and developed as one of the most promising power source candidates for various applications including electric vehicles, stationary power stations and portable devices due to its high efficiency and low emissions. However, the intrinsically sluggish reaction at the cathode, namely the oxygen reduction reaction (ORR), hinders the large-scale commercialization of the PEMFC as expensive and scarce platinum-based catalysts are used to accelerate this reaction. In order to reduce the cost of PEMFC, non-precious metal catalyst (NPMC) towards ORR has been developed and already brought itself from a pure scientific curiosity to a practically viable option for some commercial applications. In this work, two classes of low-cost NPMCs are investigated. One class is composed of high temperature treated transition metal-nitrogen-carbon M-N-C (M=Fe, Co) complex catalyst, especially iron-nitrogen-carbon complex (Fe-N-C) catalyst. These materials can demonstrate decent ORR activity and durability and provide high power output at moderate operating voltages. The other class with an even lower cost is the metal-free catalyst, which omits the metal content from M-N-C catalysts completely. This type of catalyst demonstrates excellent durability, especially in the presence of species that can cause contamination (e.g. carbon monoxide) or species that can cross-over (e.g. methanol). These two classes of NPMCs are developed and delivered with the ultimate objective of achieving a significant cost reduction in PEMFC while maintaining excellent PEMFC performance and durability. Herein, the research in this thesis starts with novel N, S-co-doped Fe-N-C catalysts to meet the objective of obtaining a highly economical and efficient NPMC. The catalyst is fabricated via pyrolyzing the composite of in-situ polymerized novel N, S-co-containing precursor, polyrhodanine (PRh) onto the acid-treated carbon black via the initiation of FeCl3. The N, S-co-doped Fe-N-C catalyst is obtained after two heat-treatment steps with one acid-leaching step in between. The catalyst demonstrates excellent ORR activity, bearing a half-wave potential of 0.77 V vs RHE in the acidic electrolyte. It also shows an excellent H2-air PEMFC performance, ranking the obtained peak power density (386 mW cm-2 at 0.46 V) among the best reported NMPC catalyst in H2-air PEMFC in the world. The N, S-co-doped Fe-N-C catalyst tends to catalyze the oxygen reduction via four electron pathway according to its number of transferred electrons (>3.94) and low peroxide yield (

Download or read book Catalysis for Low Temperature Fuel Cells written by Vincenzo Baglio and published by MDPI. This book was released on 2018-03-23 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Catalysis for Low Temperature Fuel Cells" that was published in Catalysts

Download or read book Electrocatalytic and Fuel Processing Studies for Portable Fuel Cells written by Paul H. Matter and published by . This book was released on 2006 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In the field of catalysis, the development of alternative catalysts for the oxygen reduction reaction (ORR) in Polymer Electrolyte Membrane Fuel Cell (PEMFC) cathodes has been an ongoing task for researchers over the past two decades. Currently, the high expense and low availability of platinum will hinder the large-scale commercialization of PEM fuel cells. The most hopeful advances being made in replacing platinum are related to pyrolyzed organic macrocycles with transition metal centers (such as Fe or Co porphyrins and phthalocyanines). Encouragingly, it has recently been discovered that active electrodes could be prepared by heat-treating metal and nitrogen precursors (not necessarily organic macrocycles) together in the presence of a carbon support. In the first study of this dissertation, catalysts for the Oxygen Reduction Reaction (ORR) were prepared by the pyrolysis of acetonitrile over various supports. The supports used included Vulcan Carbon, high purity alumina, silica, magnesia, and these same supports impregnated with Fe, Co, or Ni in the form of acetate salt. The catalysts were characterized by N2 physisorption, conductivity testing, Transmission Electron Microscopy (TEM), Temperature Programmed Oxidation (TPO), Thermo-Gravimetric Analysis (TGA), X-Ray Diffraction (XRD), X-ray Photo-electron Spectroscopy (XPS), Mössbauer Spectroscopy, Rotating Ring-Disk Electrode (RRDE) half cell testing, and full PEMFC testing. The most active catalysts were formed when Fe was added to the support before the pyrolysis; however, samples in which no metal was added still showed elevated activity for oxygen reduction. Within a support family, the more active catalysts had a higher amount of pyridinic nitrogen, as determined from XPS. A theory has been proposed to explain this trend based on the formation of different nanostructures depending on which support material is used for the acetonitrile decomposition. According to this theory, nitrogen-containing carbon samples with nanostructures that result in more edge planes being exposed (the plane in which pyridinic nitrogen is found) will be more active for the ORR. In volume II of this dissertation, Cu-based catalysts for hydrogen production from methanol and water were studied. These catalysts have applications for mobile fuel cells that rely on hydrogen production from easier to store liquid fuels, such as methanol.

Download or read book Polymer Electrolyte Fuel Cell Durability written by Felix N. Büchi and published by Springer Science & Business Media. This book was released on 2009-02-08 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers a significant number of R&D projects, performed mostly after 2000, devoted to the understanding and prevention of performance degradation processes in polymer electrolyte fuel cells (PEFCs). The extent and severity of performance degradation processes in PEFCs were recognized rather gradually. Indeed, the recognition overlapped with a significant number of industrial dem- strations of fuel cell powered vehicles, which would suggest a degree of technology maturity beyond the resaolution of fundamental failure mechanisms. An intriguing question, therefore, is why has there been this apparent delay in addressing fun- mental performance stability requirements. The apparent answer is that testing of the power system under fully realistic operation conditions was one prerequisite for revealing the nature and extent of some key modes of PEFC stack failure. Such modes of failure were not exposed to a similar degree, or not at all, in earlier tests of PEFC stacks which were not performed under fully relevant conditions, parti- larly such tests which did not include multiple on–off and/or high power–low power cycles typical for transportation and mobile power applications of PEFCs. Long-term testing of PEFCs reported in the early 1990s by both Los Alamos National Laboratory and Ballard Power was performed under conditions of c- stant cell voltage, typically near the maximum power point of the PEFC.

Download or read book Proton Exchange Membrane Fuel Cells 9 written by T. Fuller and published by The Electrochemical Society. This book was released on 2009-09 with total page 2100 pages. Available in PDF, EPUB and Kindle. Book excerpt: This issue of ECS Transactions is devoted to all aspects of research, development, and engineering of proton exchange membrane (PEM) fuel cells and attacks, as well as low-temperature direct-fuel cells. The intention of the symposium is to bring together the international community working on the subject and to enable effective interactions between the research and engineering communities. This issue is sold as a two-part set.

Download or read book Electrocatalysis in Fuel Cells written by Minhua Shao and published by Springer Science & Business Media. This book was released on 2013-04-08 with total page 748 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel cells are one of the most promising clean energy conversion devices that can solve the environmental and energy problems in our society. However, the high platinum loading of fuel cells - and thus their high cost - prevents their commercialization. Non- or low- platinum electrocatalysts are needed to lower the fuel cell cost. Electrocatalysis in Fuel Cells: A Non and Low Platinum Approach is a comprehensive book summarizing recent advances of electrocatalysis in oxygen reduction and alcohol oxidation, with a particular focus on non- and low-Pt electrocatalysts. All twenty four chapters were written by worldwide experts in their fields. The fundamentals and applications of novel electrocatalysts are discussed thoroughly in the book. The book is geared toward researchers in the field, postgraduate students and lecturers, and scientists and engineers at fuel cell and automotive companies. It can even be a reference book for those who are interested in this area.

Download or read book Plasma Functionalization of Graphene Nanoflakes for Non noble Catalyst in Fuel Cells written by Dustin Binny and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Two major obstacles currently limit the commercial viability of proton exchange membrane fuel cells (PEMFCs): cost and operating life. The most important contribution to the high cost of these systems is the use of platinum (Pt) as a catalyst, especially on the cathode where the oxygen reduction reaction (ORR) takes place. This thesis is part of the intensive international research efforts to find an alternative substitute for platinum. Doped carbon nanomaterials have been identified as a potential replacement for platinum ORR-electrocatalyst due to their excellent electrical conductivity and chemical resistance in acidic and basic environments. By doping the carbon nanomaterials with nitrogen, in the preferred pyridinic and quaternary forms, iron can be coordinated to complete the catalytic sites on an atomic scale. Nanocrystalline powder has recently been developed in the Plasma Processing Laboratory (PPL) at McGill University. The particles constituting the powder, in the form of graphene nanoflakes (GNFs), are formed by the superposition of ten graphene layers on average and have a spatial extension on the order of hundreds of nanometers. These planes have many terminating edges upon which nitrogen can be incorporated due to their high reactivity. The crystallinity also leads to a highly stable material paving the way for a promising catalyst replacement in the PEMFC.The objective of this thesis is to take these crystalline GNFs and dope them with nitrogen in high quantities on the edges of the graphene planes in pyridinic and quaternary forms to create the catalytic sites necessary for ORR. An inductively-coupled thermal plasma (ICP) is used to dissociate methane at very high temperatures, with homogeneous GNF nucleation commencing shortly after by way of rapid quenching. Nitrogen doping occurs in a second treatment phase by manipulating plasma conditions in order to create excited and dissociated nitrogen species that react at the edges of the GNFs.Nitrogen doping up to 33.4 at.%Ntotal has been demonstrated, which bests any other nitrogen-doped graphene by at least a factor of 2.6 and even the best nitrogen-doped carbonaceous material by 67%. Pyridinic and quaternary nitrogen constitute 8.2 at.%Npyrid and 4.9 at.%Nquat, respectively. This has been done whilst maintaining the crystalline structure and without introducing defects or impurities that would otherwise affect crystallinity and durability of these materials in future potential applications. Sequential in-situ GNF synthesis and deposition/dispersion onto a carbon cloth, which functions as the gas diffusion layer (GDL) in fuel cells, has also been demonstrated. Solid anchoring of the deposited GNFs on the individual carbon fibers is observed, and columnar growth with open film porosity reveals GNF films of micrometer-scale thicknesses. These films also exhibit desirable properties required for the ORR: porosity, homogeneity over a large area, good contact to the electrical transport throughout the network of particles and accessibility to the catalytic sites. The obtained properties seem in fact unmatched by catalytic particle ink applications commonly used in the manufacture of the catalyst layer. This in-situ work is promising and original, establishing a potential new method of producing membrane electrode assemblies (MEAs) in PEM fuel cell manufacturing.This new graphene nanomaterial could also pave the way for its potential use in supercapacitors, solar cells, biosensors, batteries, fuel storage, field-effect transistors, filtration and electrochemical devices, in addition to the fuel cell catalysis applications under study." --

Download or read book PEM Fuel Cell Electrocatalysts and Catalyst Layers written by Jiujun Zhang and published by Springer Science & Business Media. This book was released on 2008-08-26 with total page 1147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane (PEM) fuel cells are promising clean energy converting devices with high efficiency and low to zero emissions. Such power sources can be used in transportation, stationary, portable and micro power applications. The key components of these fuel cells are catalysts and catalyst layers. “PEM Fuel Cell Electrocatalysts and Catalyst Layers” provides a comprehensive, in-depth survey of the field, presented by internationally renowned fuel cell scientists. The opening chapters introduce the fundamentals of electrochemical theory and fuel cell catalysis. Later chapters investigate the synthesis, characterization, and activity validation of PEM fuel cell catalysts. Further chapters describe in detail the integration of the electrocatalyst/catalyst layers into the fuel cell, and their performance validation. Researchers and engineers in the fuel cell industry will find this book a valuable resource, as will students of electrochemical engineering and catalyst synthesis.