Download or read book Synthesis and Characterization of Electrocatalyst Libraries for PEM Fuel Cells written by Kousik Ganesan and published by . This book was released on 2005 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conversion of energy stored in renewable fuels for sustained and environment friendly operation necessitates new technologies. Polymer electrolyte membrane fuel cells represent an energy conversion technology that has advantages of high operating efficiencies with low hazardous emissions. However the discovery of more active and poison tolerant catalysts for anode and cathode reactions remains a major barrier to commercialization of this technology. The search for improved catalyst formulations is hindered by the massive parameter space available for their construction. Combinatorial methods represent an exploration process well suited to accelerate this discovery through the ability to generate and screen a multitude of compositions in a single experiment. In this work, we describe a combinatorial strategy to generate a wide variety of catalyst compositions (single/binary) and interrogate their activity directly in an electrochemical environment. Catalyst library fabrication tools based upon array deposition methods were used to prepare samples possessing catalyst combinations containing Pt and additional metals such as Ru, Rh, Mo, Ir, Nb, Ta, Pd, Sn, Os and W. High throughput screening of catalytic activity was accomplished by scanning electrochemical microscopy (SECM). Reactivity maps were constructed by directly measuring the kinetics of hydrogen oxidation with a scanning microelectrode probe in the presence and absence of adsorbed carbon monoxide. Results provide quantitative rate constants for hydrogen oxidation and poison tolerance over a broad sampling of catalyst compositions.
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.
Download or read book Synthesis and Characterization of CO and H2S Tolerant Electrocatalysts for PEM Fuel Cell written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present state-of-art Proton Exchange Membrane Fuel Cell (PEMFC) technology is based on platinum (Pt) as a catalyst for both the fuel (anode) and air (cathode) electrodes. This catalyst is highly active but susceptible to poisoning by CO, which may be present in the H2-fuel used or may be introduced during the fuel processing. Presence of trace amount of CO and H2S in the H2-fuel poisons the anode irreversibly and decreases the performance of the PEMFCs. In an effort to reduce the Pt-loading and improve the PEMFC performance, we propose to synthesize a number of Pt-based binary, ternary, and quaternary electrocatalysts using Ru, Mo, Ir, Ni, and Co as a substitute for Pt. By fine-tuning the metal loadings and compositions of candidate electrocatalysts, we plan to minimize the cost and optimize the catalyst activity and performance in PEMFC. The feasibility of the novel electrocatalysts will be demonstrated in the proposed effort with gas phase CO and H2S concentrations typical of those found in reformed fuel gas with coal/natural gas/methanol feedstocks. In this work binary, ternary, and quaternary platinum-based electrocatalysts were synthesized for the purpose of lowering the cost and increasing the CO tolerance of the membrane electrode assembly (MEA) in the fuel cell. The metals Ru, Mo, W, Ir, Co and Se were alloyed with platinum on a carbon support using a modified reduction method. These catalysts were fabricated into MEAs and evaluated for electrical performance and CO tolerance with polarization experiments. The quaternary system Pt/Ru/Mo/Ir system is the most CO tolerant in the PEMFC and has a low total metal loading of 0.4 mg/cm2 in the electrode of the cell.
Download or read book Electrocatalysis for Membrane Fuel Cells written by Nicolas Alonso-Vante and published by John Wiley & Sons. This book was released on 2023-12-11 with total page 581 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electrocatalysis for Membrane Fuel Cells Comprehensive resource covering hydrogen oxidation reaction, oxygen reduction reaction, classes of electrocatalytic materials, and characterization methods Electrocatalysis for Membrane Fuel Cells focuses on all aspects of electrocatalysis for energy applications, covering perspectives as well as the low-temperature fuel systems principles, with main emphasis on hydrogen oxidation reaction (HOR) and the oxygen reduction reaction (ORR). Following an introduction to basic principles of electrochemistry for electrocatalysis with attention to the methods to obtain the parameters crucial to characterize these systems, Electrocatalysis for Membrane Fuel Cells covers sample topics such as: Electrocatalytic materials and electrode configurations, including precious versus non-precious metal centers, stability and the role of supports for catalytic nano-objects; Fundamentals on characterization techniques of materials and the various classes of electrocatalytic materials; Theoretical explanations of materials and systems using both Density Functional Theory (DFT) and molecular modelling; Principles and methods in the analysis of fuel cells systems, fuel cells integration and subsystem design. Electrocatalysis for Membrane Fuel Cells quickly and efficiently introduces the field of electrochemistry, along with synthesis and testing in prototypes of materials, to researchers and professionals interested in renewable energy and electrocatalysis for chemical energy conversion.
Download or read book Synthesis Characterization and Design of Novel Fuel Cell Electro oxidation Catalysts written by Aurora Marie Cabrera Fojas and published by . This book was released on 2004 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book written by and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Nanostructured Electrocatalysts for Proton Exchange Membrane and Direct Methanol Fuel Cells written by Liufeng Xiong and published by . This book was released on 2004 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC) are attractive power sources as they offer high conversion efficiencies with low or no pollution. However, the most commonly used platinum electrocatalyst is expensive and the world supply of Pt is limited. In addition, the slow oxygen reduction and methanol oxidation kinetics as well as the poisoning of the Pt catalyst at the cathode resulting from methanol permeation from the anode through the Nafion membrane to the cathode lead to significant performance loss. Also, the electrocatalyst utilization in the electrodes also needs to be improved to reduce the overall cost of the electrocatalysts and improve the fuel cell performance. This dissertation explores nanostructured Pt alloys with lower cost and higher catalytic activity than Pt for oxygen reduction in PEMFC to understand the effect of synthesis and structure on the catalytic activity, methanol tolerant Pt/TiOx nanocomposites for oxygen reduction in DMFC, nanostructured Pt-Ru alloys for methanol oxidation in DMFC, and improvement in the utilization of Pt by optimizing the membrane-electrode assembly (MEA) fabrication. From a systematic investigation of a series of Pt-M alloys (M = Fe, Co, Ni, and Cu), the catalytic activity of Pt-M alloys is correlated with the extent of atomic ordering. More ordered Pt alloys exhibit higher catalytic activity than disordered Pt alloys. The higher activity of the ordered Pt alloys is found to relate to various factors including the Pt-Pt distance, Pt: 5d orbital vacancy, {100} planar density and surface atomic configuration. The catalytic activity of the Pt alloys is also influenced by the synthesis method. Low temperature solution methods usually result in smaller particle size and higher surface area, while high temperature routes result in larger particle size and lower surface area but with a greater extent of alloying. Pt/TiOx/C nanocomposites exhibit higher performance than Pt for oxygen reduction in DMFC. The nanocomposites show higher electrchochemical surface area, lower charge transfer resistance, and higher methanol tolerance than Pt. Pt-Ru alloy synthesized by a reverse microemulsion method exhibits higher catalytic surface area than the commercial Pt-Ru. The higher catalytic activity is attributed to a better control of the particle size, crystallinity, and microstructure. Membrane-electrode assemblies (MEAs) fabricated by a modified thin film method exhibit much higher electrocatalyst utilization efficiency and performance than the conventional MEAs in PEMFC. Power densities of 715 and 610 mW/cm2 are obtained at a Pt loading of, respectively, 0.1 and 0.05 mg/cm2 and 90 oC. The higher electrocatalyst utilization is attributed to the thin catalyst layer and a better continuity of the membrane/catalysts layer interface compared to that in the conventional MEAs.
Download or read book Preparation and Characterization of Highly Active Nano Pt C Electrocatalyst for Proton Exchange Membrane Fuel Cell written by Qiling Ying and published by . This book was released on 2006 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysts play and essential role in nearly every chemical production process. Platinum supported on high surface area carbon substrates (Pt/C) is one of the promising candidates as an electrocatalyst in low temperature polymer electrolyte fuel cells. Developing the activity of the Pt/C catalyst with narrow Pt particle size distribution and good dispersion has been a concern in current research. In this study, the main objective was the development and characterization of inexpensive and effective nanophase Pt/C electrocatalysts.
Download or read book Design Synthesis and Characterization of Fuel Cell Electrocatalysts for the Direct Oxidation of Organic Fuels written by Aurora Marie Cabrera Fojas and published by . This book was released on 2008 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Nano Structured Electrocatalysts for Oxygen Reduction Reaction in Fuel Cells written by Thomas Jefferson Cochell and published by . This book was released on 2013 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) are two types of low-temperature fuel cells (LTFCs) that operate at temperatures less than 100 °C and are appealing for portable, transportation, and stationary applications. However, commercialization has been hampered by several problems such as cost, efficiency, and durability. New electrocatalysts must be developed that have higher oxygen reduction reaction (ORR) activity, lower precious metal loadings, and improved durability to become commercially viable. This dissertation investigates the development and use of new electrocatalysts for the ORR. Core-shell (shell@core) Pt@Pd[subscript x]Cu[subscript y]/C electrocatalysts, with a range of initial compositions, were synthesized to result in a Pt-rich shell atop a Pd[subscript x]C[subscript y]-rich core. The interaction between core and shell resulted in a delay in the onset of Pt-OH formation, accounting in a 3.5-fold increase in Pt-mass activity compared to Pt/C. The methanol tolerance of the core-shell Pt@PdCu5/C was found to decrease with increasing Pt-shell coverage due to the negative potential shift in the CO oxidation peak. It was discovered that Cu leached out from the cathode has a detrimental effect on membrane-electrode assembly performance. A spray-assisted impregnation method was developed to reduce particle size and increase dispersion on the support in a consistent manner for a Pd88W12/C electrocatalyst. The spray-assisted method resulted in decreased particle size, improved dispersion and more uniform drying compared to a conventional method. These differences resulted in greater performance during operation of a single DMFC and PEMFC. Additionally, Pd88W12/C prepared by spray-assisted impregnation showed DMFC performance similar to Pt/C with similar particle size in the kinetic region while offering improved methanol tolerance. Pd88W12/C also showed comparable maximum power densities and activities normalized by cost in a PEMFC. Lastly, the activation of aluminum as an effective reducing agent for the wet- chemical synthesis of metallic particles by pitting corrosion was explored along with the control of particle morphology. It was found that atomic hydrogen, an intermediate, was the actual reducing agent, and a wide array of metals could be produced. The particle size and dispersion of Pd/C produced using Al was controlled using PVP and FeCl2 as stabilizers. The intermetallic Cu2Sb was similarly prepared with a 20 nm crystallite size for potential use in lithium-ion battery anodes. Lastly, it was found that the shape of Pd produced with Al as a reducing agent could be controlled to prepare 10 nm cubes enclosed by (100) facets with potentially high activity for the ORR.
Download or read book SYNTHESIS AND CHARACTERIZATION OF CO AND H sub 2 S TOLERANT ELECTROCATALYSTS FOR PEM FUEL CELL written by Shamsuddin Ilias and published by . This book was released on 2005 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present state-of-art Proton Exchange Membrane Fuel Cell (PEMFC) technology is based on platinum (Pt) as a catalyst for both the fuel (anode) and air (cathode) electrodes. This catalyst is highly active but susceptible to poisoning by CO, which may be present in the H{sub 2}-fuel used or may be introduced during the fuel processing. Presence of trace amount of CO and H{sub 2}S in the H{sub 2}-fuel poisons the anode irreversibly and decreases the performance of the PEMFCs. In an effort to reduce the Pt-loading and improve the PEMFC performance, we propose to synthesize a number of Pt-based binary, ternary, and quaternary electrocatalysts using Ru, Mo, Ir, Ni, and Co as a substitute for Pt. By fine-tuning the metal loadings and compositions of candidate electrocatalysts, we plan to minimize the cost and optimize the catalyst activity and performance in PEMFC. The feasibility of the novel electrocatalysts will be demonstrated in the proposed effort with gas phase CO and H{sub 2}S concentrations typical of those found in reformed fuel gas with coal/natural gas/methanol feedstocks. During this reporting period several tri-metallic electrocatalysts were synthesized using both ultra-sonication and conventional method. These catalysts (Pt/Ru/Mo, Pt/Ru/Ir, Pt/Ru/W, Ptr/Ru/Co, and Pt/Ru/Se on carbon) were tested in MEAs. From Galvonstatic study the catalytic activity was found in the order of: Pt/Ru/Mo/C> Pt/Ru/Ir/C> Pt/Ru/W/C> Ptr/Ru/Co/C> and Pt/Ru/Se. It appears that electrocatalysts prepared by ultra-sonication process are more active compared to the conventional technique. Work is in progress to further study these catalysts for CO-tolerance in PEMFC.
Download or read book Heterogeneous Catalysts written by Wey Yang Teoh and published by John Wiley & Sons. This book was released on 2021-02-23 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents state-of-the-art knowledge of heterogeneous catalysts including new applications in energy and environmental fields This book focuses on emerging techniques in heterogeneous catalysis, from new methodology for catalysts design and synthesis, surface studies and operando spectroscopies, ab initio techniques, to critical catalytic systems as relevant to energy and the environment. It provides the vision of addressing the foreseeable knowledge gap unfilled by classical knowledge in the field. Heterogeneous Catalysts: Advanced Design, Characterization and Applications begins with an overview on the evolution in catalysts synthesis and introduces readers to facets engineering on catalysts; electrochemical synthesis of nanostructured catalytic thin films; and bandgap engineering of semiconductor photocatalysts. Next, it examines how we are gaining a more precise understanding of catalytic events and materials under working conditions. It covers bridging pressure gap in surface catalytic studies; tomography in catalysts design; and resolving catalyst performance at nanoscale via fluorescence microscopy. Quantum approaches to predicting molecular reactions on catalytic surfaces follows that, along with chapters on Density Functional Theory in heterogeneous catalysis; first principles simulation of electrified interfaces in electrochemistry; and high-throughput computational design of novel catalytic materials. The book also discusses embracing the energy and environmental challenges of the 21st century through heterogeneous catalysis and much more. Presents recent developments in heterogeneous catalysis with emphasis on new fundamentals and emerging techniques Offers a comprehensive look at the important aspects of heterogeneous catalysis Provides an applications-oriented, bottoms-up approach to a high-interest subject that plays a vital role in industry and is widely applied in areas related to energy and environment Heterogeneous Catalysts: Advanced Design, Characterization and Applications is an important book for catalytic chemists, materials scientists, surface chemists, physical chemists, inorganic chemists, chemical engineers, and other professionals working in the chemical industry.
Download or read book Synthesis and Characterization of Novel Electrocatalysts and Supports for Use in Polymer Electrolyte Membrane Fuel Cells written by Nicolaus L. Rock and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electrocatalysis in Fuel Cells written by Minhua Shao and published by MDPI. This book was released on 2018-09-28 with total page 689 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Electrocatalysis in Fuel Cells" that was published in Catalysts
Download or read book Fundamentals of Electrocatalyst Materials and Interfacial Characterization written by Nicolas Alonso-Vante and published by John Wiley & Sons. This book was released on 2019-02-28 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses some essential topics in the science of energy converting devices emphasizing recent aspects of nano-derived materials in the application for the protection of the environment, storage, and energy conversion. The aim, therefore, is to provide the basic background knowledge. The electron transfer process and structure of the electric double layer and the interaction of species with surfaces and the interaction, reinforced by DFT theory for the current and incoming generation of fuel cell scientists to study the interaction of the catalytic centers with their supports. The chief focus of the chapters is on materials based on precious and non-precious centers for the hydrogen electrode, the oxygen electrode, energy storage, and in remediation applications, where the common issue is the rate-determining step in multi-electron charge transfer processes in electrocatalysis. These approaches are used in a large extent in science and technology, so that each chapter demonstrates the connection of electrochemistry, in addition to chemistry, with different areas, namely, surface science, biochemistry, chemical engineering, and chemical physics.
Download or read book Fuel Cell Science written by Andrzej Wieckowski and published by John Wiley & Sons. This book was released on 2011-02-14 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive survey of theoretical andexperimental concepts in fuel cell chemistry Fuel cell science is undergoing significant development, thanks, in part, to a spectacular evolution of the electrocatalysis concepts, and both new theoretical and experimental methods. Responding to the need for a definitive guide to the field, Fuel Cell Science provides an up-to-date, comprehensive compendium of both theoretical and experimental aspects of the field. Designed to inspire scientists to think about the future of fuel cell technology, Fuel Cell Science addresses the emerging field of bio-electrocatalysis and the theory of heterogeneous reactions in fuel cell science and proposes potential applications for electrochemical energy production. The book is thorough in its coverage of the electron transfer process and structure of the electric double layer, as well as the development of operando measurements. Among other subjects, chapters describe: Recently developed strategies for the design, preparation, and characterization of catalytic materials for fuel cell electrodes, especially for new fuel cell cathodes A wide spectrum of theoretical and computational methods, with?the aim of?developing?new fuel cell catalysis concepts and improving existing designs to increase their performance.? Edited by two leading faculty, the book: Addresses the emerging fields of bio-electrocatalysis for fuel cells and theory of heterogeneous reactions for use in fuel cell catalysis Provides a survey of experimental and theoretical concepts in these new fields Shows the evolution of electrocatalysis concepts Describes the chemical physics of fuel cell reactions Forecasts future developments in electrochemical energy production and conversion Written for electrochemists and electrochemistry graduate students, electrocatalysis researchers, surface and physical chemists, chemical engineers, automotive engineers, and fuel cell and energy-related researchers, this modern compendium can help today's best minds meet the challenges in fuel science technology.
Download or read book Platinum Monolayer Electrocatalysts written by Radoslav Adzic and published by Springer Nature. This book was released on 2020-08-11 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes a science and technology of a new type of electrocatalysts consisting of a single atomic layer of platinum on suitable supports. This development helped overcome three major obstacles—catalysts‘ cost, activity, and stability—for a broad range of fuel cell applications. The volume begins with a short introduction to the science of electrocatalysis, covering four reactions important for energy conversion in fuel cells. A description follows of the properties of metal monolayers on electrode surfaces, and underpotential deposition of metals. The authors then describe the concept of Pt monolayer electrocatalysts and its implications and their synthesis by galvanic displacement of less-noble metal monolayers and other methods. The main part of the book presents a discussion of catalysts’ characterization and catalytic properties of Pt monolayers for the four main reactions of electrochemical energy conversion: oxygen reduction and oxidation of hydrogen, methanol and ethanol. The book concludes with a treatment of scale-up syntheses, fuel cell tests, catalysts’ stability and application prospects.
