Download or read book Fabrication of Platinum Catalyst and Novel Supports by Atomic Layer Deposition for Fuel Cell Application written by 金子剛 and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fabrication of Platinum Catalyst on Novel Porous Supports by Atomic Layer Deposition for High Specific Power Density Proton Exchange Membrane Fuel Cell and Its Accelerated Degradation Test written by 薛仰志 and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book Nanostructured and Advanced Materials for Fuel Cells written by San Ping Jiang and published by CRC Press. This book was released on 2013-12-07 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boasting chapters written by leading international experts, Nanostructured and Advanced Materials for Fuel Cells provides an overview of the progress that has been made so far in the material and catalyst development for fuel cells. The book covers the most recent developments detailing all aspects of synthesis, characterization, and performance. It offers an overview on the principles, classifications, and types of fuels used in fuel cells, and discusses the critical properties, design, and advances made in various sealing materials. It provides an extensive review on the design, configuration, fabrication, modeling, materials, and stack performance of μ-SOFC technology, and addresses the advancement and challenges in the synthesis, characterization, and fundamental understanding of the catalytic activity of nitrogen-carbon, carbon, and noncarbon-based electro catalysts for PEM fuel cells. The authors explore the atomic layer deposition (ALD) technique, summarize the advancements in the fundamental understanding of the most successful Nafion membranes, and focus on the development of alternative and composite membranes for direct alcohol fuel cells (DAFCs). They also review current challenges and consider future development in the industry. Includes 17 chapters, 262 figures, and close to 2000 references Provides an extensive review of the carbon, nitrogen-carbon, and noncarbon-based electro catalysts for fuel cells Presents an update on the latest materials development in conventional fuel cells and emerging fuel cells This text is a single-source reference on the latest advances in the nano-structured materials and electro catalysts for fuel cells, the most efficient and emerging energy conversion technologies for the twenty-first century. It serves as a valuable resource for students, materials engineers, and researchers interested in fuel cell technology.

Download or read book Novel Catalyst Synthesis Methods for Fuel Cell Applications written by Irene J. Hsu and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many resources have been devoted to developing novel catalytic systems in efforts to improve the activity of electrochemical reactions while more efficiently utilizing the precious metal catalyst. However, in order for these catalyst systems to be relevant industrially they must be in the form of particles. Conventional synthesis methods are too simplistic for these systems, which require a higher level of control in their synthesis. Atomic layer deposition (ALD) was used to deposit Pt layers on tungsten monocarbide (WC) particles in an effort to produce monolayer Pt-WC catalysts. DFT calculations predicted that one monolayer of Pt on a WC substrate should perform as well as a Pt catalyst for the ORR. Pt ALD was first demonstrated on WC thin films and the growth and nucleation characteristics were studied. A nucleation period was observed where the growth per cycle was quite slow; after which the growth rate increased considerably. When few ALD cycles were used, Pt particles were well dispersed on the WC surface, but eventually with increased ALD cycles, merged to form a continuous layer. Pt monolayer growth is difficult on WC because there are few available adsorption sites for the Pt precursor, and discrete Pt particles are created instead. With increasing ALD cycles, existing Pt particles are more likely to grow rather than nucleate elsewhere on the WC surface. Therefore, in order to make thinner Pt layers the nucleation density must be increased at low ALD cycles. Pt ALD was then applied to WC powders to compare growth characteristics with the thin films. TEM imaging and Cu stripping voltammetry found that Pt ALD growth on the WC powder substrate was similar to that on WC thin films. However, the presence of excess free carbon was found to affect Pt ALD on WC powders by blocking adsorption sites on WC and also providing its own sites for Pt particle nucleation. Despite this, the ALD Pt-WC powders were found to be electrochemically equivalent to the ALD Pt-WC thin films through cyclic voltammogram analysis. The Pt-WC powders were also analyzed for ORR using a rotating disk electrode apparatus to obtain quantitative activity information. The mass specific and specific activities for the 30 and 50 ALD cycle samples were found to be comparable to a 10 wt% Pt/C catalyst with more than half the Pt loading. However, the oxygen reduction mechanism on the Pt-WC catalysts was found to be less efficient than on the Pt/C catalyst. Higher overpotentials were observed, and the reduction was found to take the 2-electron peroxide reduction pathway, the less desirable pathway for fuel cell applications. To explain some of the observations in electrochemical activity found with the ALD Pt-WC samples, WC disks with one monolayer of Pt were produced to make idealized surfaces. This system was found to have a lower-than-expected ORR activity, which was attributed to the lack of stability of the WC substrate in oxygen-saturated acid media. Regardless, the Pt-WC core shell system could be potentially useful for other reaction systems, such as hydrogen evolution reaction. Additionally, shape-controlled Pt particles were produced using pulse electrodeposition. By adjusting the applied potential, Pt particles that are spherical, cubic, or dendritic can be made. These were also shown to be useful for the methanol oxidation, a structure sensitive reaction. The dendritic particles were confirmed to be more active than cubic particles, which is in agreement with the literature.

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 Optimization of Carbon Supported Platinum Catalysts for Fuel Cell Electrodes written by H. R. Kunz and published by . This book was released on 1980 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this program was to optimize electrodes using the carbon-supported platinum catalysts at the operating conditions required for use in methanol-air, phosphoric-acid electrolyte, fuel cell power plants for U.S. Army applications. Cathodes using proprietary, supported-platinum catalyst, GSA-6, were fabricated with various degrees of hydrophobicity by adjusting the Teflon content in the catalyst layer and by changing the Teflon sintering cycle. These cathodes were tested with supported-platinum anodes in eighteen subscale cells at the Army power plant operating conditions for periods exceeding 5000 hours. The optimum structure, on the basis of peak cell voltage, endurance stability, and manufacturing reproducibility was found to be one containing 47.5% Teflon. A standard United proprietary anode catalyst showed satisfactory peak performance and endurance stability. The cells with optimized electrodes exceeded the program 500-hour performance goal of 0.620V at 200 mA/cubic centimeters by 0.020V. The 6000-hour performance goal of 0.590 V at 200 mA/cubic centimeters was projected to be exceeded by 0.036 to 0.038 V (based on over 4000 hours of operation).

Download or read book Developing Uniform and Novel Supported Palladium Catalysts Grown by Atomic Layer Deposition written by and published by . This book was released on 2013 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first method established a procedure for producing palladium nanoparticles on single crystal substrates using atomic layer deposition. These materials were highly uniform and contained low levels of surface contamination. They were used to study the adsorption of alcohol oxidation reactants and over-oxidation products at the catalyst-reaction medium interface using sum frequency generation spectroscopy.

Download or read book Direct Liquid Fuel Cells written by Ramiz Gültekin Akay and published by Academic Press. This book was released on 2020-09-10 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct Liquid Fuel Cells is a comprehensive overview of the fundamentals and specificities of the use of methanol, ethanol, glycerol, formic acid and formate, dimethyl ether, borohydride, hydrazine and other promising liquid fuels in fuel cells. Each chapter covers a different liquid fuel-based fuel cell such as: Anode catalysts of direct methanol fuel cells (DMFCs), future system designs and future trends for direct ethanol fuel cells (DEFCs), development of catalysts for direct glycerol fuel cells (DGFCs), the mechanisms of the reactions taking place at the anode and cathode electrodes, and the reported anode catalysts for direct formic acid fuel cell (DFAFC) and direct formate fuel cell (DFFC), characteristics of direct dimethyl ether fuel cell (DDMEFC), including its electrochemical and operating systems and design, the developments in direct borohydride fuel cells, the development of catalysts for direct hydrazine fuel cells (DHFCs), and also the uncommonly used liquids that have a potential for fuel cell applications including 2-propanol, ethylene glycol, ascorbic acid and ascorbate studied in the literature as well as utilization of some blended fuels. In each part, the most recent literature is reviewed and the state of the art is presented. It also includes examples of practical problems with solutions and a summarized comparison of performance, advantages, and limitations of each type of fuel cell discussed. Direct Liquid Fuel Cells is not a typical textbook but rather designed as a reference book of which any level of students (undergraduate or graduate), instructors, field specialists, industry and general audience, who benefit from current and complete understanding of the many aspects involved in the development and operation of these types of fuel cells, could make use of any chapter when necessary. Presents information on different types of direct liquid fuel cells. Explores information under each section, for specific fuel-based fuel cells in more detail in terms of the materials used. Covers three main sections: direct alcohol, organic fuel-based and inorganic fuel-based fuel cells

Download or read book Electrocatalysts by Atomic Layer Deposition for Fuel Cell Applications written by and published by . This book was released on 2016 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, fuel cells are a promising technology solution for reliable and clean energy because they offer high energy conversion efficiency and low emission of pollutants. However, high cost and insufficient durability are considerable challenges for widespread adoption of polymer electrolyte membrane fuel cells (PEMFCs) in practical applications. Current PEMFCs catalysts have been identified as major contributors to both the high cost and limited durability. Atomic layer deposition (ALD) is emerging as a powerful technique for solving these problems due to its exclusive advantages over other methods. In this review, we summarize recent developments of ALD in PEMFCs with a focus on design of materials for improved catalyst activity and durability. New research directions and future trends have also been discussed.

Download or read book Fabrication of Pt Catalyst on TiN Inverse Opal Structure for Proton Exchange Membrane Fuel Cell by Atomic Layer Deposition written by 劉又榮 and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Improving the Durability of Nanostructured Thin Film Supported Platinum Fuel Cell Catalysts with the Addition of Iridium and Ruthenium written by Timothy Crowtz and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the remaining challenges driving polymer electrolyte membrane hydrogen fuel cell research is the durability of the Pt oxygen reduction reaction (ORR) catalyst. Pt is inherently unstable; minute amounts (in the order of ng/cm2 are dissolved every time the fuel cell is started, goes from idle to load, or shut-down. In addition, corrosion of carbon-based materials (ubiquitous inside fuel cells) occurs during the start-up and shut-down and also contributes to the steady decline of fuel cell performance. Adding oxygen evolution reaction (OER) catalysts, of which only Ru and Ir are stable in the acidic conditions of the fuel cell, can decrease Pt loss and carbon corrosion by mitigating the degradation mechanism which occurs during the start-up and shut-down phases. There are two challenges in developing this materials solution (there are other solutions, based on hardware systems) to the fuel cell durability problem: 1) finding the right mixture of Ru and Ir, (Ru is cheaper, more active, but less stable than Ir), and 2) balancing an increase of OER activity with a loss of ORR activity due to Pt coverage by the Ru and Ir. A spread of compositions containing various amounts of Ir or Ru on 85 ug/cm2 of Pt were sputter deposited on a nanostructured thin film state-of-the art catalyst support made by 3M. The nanostructured thin film was grown by 3M on glassy carbon disks designed for a rotating disk electrode, which was used to simulate what happens to a fuel cell cathode during repeated start-up, operation, and shut-down. Experimental difficulties of glassy carbon disk corrosion were overcome with the application of high vacuum silicone grease (silicone oil and fumed silica) to the glassy carbon disk. The silicone grease did not affect the ORR activity. Ir was found to be better at protecting the ORR activity than Ru, and an Ir on Pt sputter deposition scheme was found to be better than a Ir intermixed with Pt scheme. The second study looked for ways to visualize the OER and ORR durability of about 50 of ternary (Ir on Ru on Pt) compositions. Increasing Ir loading improved the durability of both ORR and OER activity. Various Ru loadings provided little benefit except when combined with 10 ug/cm2 Ir. There was a large amount of scatter in the data. In particular some of the experiments attained a stable ORR activity, something which should not be possible given the nature of electrochemical Pt dissolution. Further work on identifying the source of these problems is needed before another catalyst screening study is done.

Download or read book Precision Synthesis with Atomic Layer Deposition for Oxygen Reduction Reaction Enhancement written by Zhaoxuan Wang and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton-exchange-membrane fuel cell (PEMFC) technology has progressed significantly over the past few decades for CO2-free energy conversion. However, the energy efficiency of PEMFCs is still far below the thermodynamic limit for numerous reasons. A major cause is the overpotential induced by the sluggish reaction kinetics, especially for oxygen reduction reaction (ORR) on the cathode. To overcome the limitation, efforts have been devoted to developing catalyst material structure engineering to maintain a high intrinsic catalytic activity. In this thesis, I will firstly discuss a strained Pt catalyst with an enhanced catalytic activity for ORR. The catalyst was fabricated by sequential atomic layer deposition(ALD) of cobalt oxide and Pt on the carbon supports, followed by acid leaching that removes almost the entire cobalt oxide template. A compressive strain in the Pt-Pt lattice of the strained catalyst was observed by both extended x-ray absorption fine structure and high-resolution transmission electron microscopy in which negligible Pt-Co interaction is found. Therefore the performance enhancement is mostly attributed to the Pt lattice strain. Secondly I will introduce a precision alloyed Pt-Ti catalyst with a Ti-rich subsurface layer. This catalyst structure was found to have a higher confidence level regarding significant catalytic activity enhancement in density functional theory model. An almost 8-fold activity enhancement compared to Pt ALD catalyst were achieved. Both dynamic secondary ion mass spectroscopy and scanning transmission electron microscopy indicate significant Ti enrichment close to the very surface. Finally, I will describe the fabrication and performance of strained Pt catalyst and Pt-Ti alloy catalyst integrated in membrane electrode assembly(MEA). To further improve the mass activity of the strained Pt catalyst, passivation gas incorporated atomic layer deposition (PALD) was applied. The mass activity was pushed to 0.59A/mg on a Ketjen Black carbon support and even close to 0.8 A/mg on CMK-3. The Ketjen Black-supported catalyst additionally demonstrated impressive durability. For Pt-Ti alloy catalyst, significant performance enhancement especially in specific activity was demonstrated. The temperature-dependent performance was studied and the Pt-Ti alloy catalyst indicates improvement in ORR performance mainly attribute to lowered activation energy barrier.

Download or read book Strong Metal Support Interaction of Pt on TiO2 Grown by Atomic Layer Deposition and Physical Vapor Deposition for Fuel Cell Applications written by Robin Paul Hansen and published by . This book was released on 2016 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Pt TiO2 C Composite Catalysts for Fuel Cells Prepared Using a Glucose Modifier written by Christopher Odetola and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysts in the electrodes of polymer exchange membrane fuel cells (PEMFCs) serve a critical function in reactions which can be used to generate electrical energy from chemical fuels. Pt nanoparticles are commonly dispersed on a conductive support and used as electrode materials in these devices because of their exceptional catalytic activity and electrochemical active surface area. The performance and stability of these electrodes strongly depend on the characteristics of the support. Catalysts supported on high surface area carbon black are widely used in low-temperature fuel cells. In PEMFCs, these catalyst materials can be exposed to high potential and low pH values, resulting in irreversible loss of activity that will limit the useful lifetime of the cell, ultimately leading to its failure. Pt is a noble metal which has good intrinsic stability, but carbon is not thermodynamically stable resulting in the corrosion of the catalyst support under these conditions. The design of more resilient platinum catalyst supports to carry out the successful reaction in a fuel cell's catalyst layer is required to extend the lifetime of PEMFCs degradation. In this thesis, two approaches were used to synthesize robust catalyst support materials for fuel cell applications. In the first case, carbon surfaces were functionalised to enhance their interactions with the catalyst and secondly, stable metal oxide was combined with modified carbon substrates, to maximise contacts within the composite electrocatalysts and to prevent carbon corrosion of a single phase carbon support catalyst. TiO2 NPs, were first chemically bonded to the surfaces of Vulcan carbon to help anchor the Pt catalyst nanoparticles through strong metal-support interactions. Validation of a dual phase catalyst support is an important goal of this research. Each material phase offers a unique advantage that can only be recognized by the preparation of a composite electrocatalyst. Pristine Vulcan (PV) was functionalised with glucose hydroxyl functional groups that react with the base titanium metal alkoxide in a sol-gel reaction and then calcined to form a more chemically crystalline surface. This is followed by impregnation reduction process to deposit the nanostructured Pt catalyst. Material characterization data of synthesized materials were used to correlate the effects of support structure and composition on resilient performance. Advantages from the TiO2/C supports toward performance and durability were contrasted against a set of control samples and demonstrated ex situ. The prepared composite catalysts showed substantial enhancements toward oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) as well as improved stability of the Pt-TiO2 heterogeneous interface formed between catalyst and support. The enhanced performance and durability of these composite catalysts is improved by applying the science of materials and interfaces to the synthesis of composite supports, thus serving as an example for further progress and optimization. Irradiation of these composite catalysts with UV-visible light also showed ~ 171 % photo enhanced activity for MOR, which clearly demonstrates a synergistic effect between the photo- and electrocatalysts. The comparison between the prepared catalysts indicates that there is an appropriate ratio of carbon and TiO2 to obtain the best performance of these photoelectroactive materials. These results demonstrate that methanol oxidation is achieved by electro- and photoelectrocatalysis using a simple and affordable method. This procedure can be conveniently exploited to enhance the response of direct methanol fuel cell electrodes.

Download or read book One dimensional Nanostructures for PEM Fuel Cell Applications written by Shangfeng Du and published by Academic Press. This book was released on 2017-08-23 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: One-dimensional Nanostructures for PEM Fuel Cell Applications provides a review of the progress made in 1D catalysts for applications in polymer electrolyte fuel cells. It highlights the improved understanding of catalytic mechanisms on 1D nanostructures and the new approaches developed for practical applications, also including a critical perspective on current research limits. The book serves as a reference for the design and development of a new generation of catalysts to assist in the realization of successful commercial use that have the potential to decarbonize the domestic heat and transport sectors. In addition, a further commercialization of this technology requires advanced catalysts to address major obstacles faced by the commonly used Pt/C nanoparticles. The unique structure of one-dimensional nanostructures give them advantages to overcome some drawbacks of Pt/C nanoparticles as a new type of excellent catalysts for fuel cell reactions. In recent years, great efforts have been devoted in this area, and much progress has been achieved. Provides a review of 1D catalysts for applications in polymer electrolyte fuel cells Presents an ideal reference for the design and development of a new generation of catalysts to assist in the realization of successful commercial use Highlights the progress made in recent years in this emerging field

Download or read book An Experimental and Computational Study of Carbon supported Platinum Alloy Fuel Cell Catalysts written by Peter Wolohan and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: