Download or read book On Tuning and Understanding Electrocatalysts for Hydrogen and Carbon based Energy Storage written by Michael T Tang and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The following thesis is a composition of published and soon-to-be published works. All works use density functional theory (DFT) calculations and descriptor-based mechanistic models to tune and screen catalytic materials for the hydrogen evolution reaction (HER) and the CO2 reduction reaction (CO2RR). In several works, experiments are included to substantiate predictions. The early sections focus on elucidating the role of key descriptors in the HER and CO2RR, specifically the H* and CO* adsorption state. It was found that nickel-gallium intermetallic systems can alter the CO* adsorption energy to achieve an early onset potential for C1 and C2 product distributions. With regards to system stability, CO* adsorption was found to induce surface refaceting towards stepped motifs on three commonly used metal catalysts, Cu, Ni, and Pt. In the latter sections, the thesis builds upon past mechanistic models to develop a multi-descriptor model that suggests new strategies to screen for better catalysts for CO2RR. It is found that not all steps may be necessarily electrochemical steps; some key intermediate steps may be surface driven, which dramatically simplifies the selectivity picture of products formed in CO2RR. As such, OH* and C* are noted as possible descriptors to use in conjunction with CO* to build potential-dependent selectivity maps that describe how the competition from the HER may affects product selectivity in CO2RR. Finally, the thesis dives into the mechanistic trends of HER, where kinetic scaling relations are calculated explicitly with a metal-water interface across multiple transition metals. It was found that the Volmer-Heyrovsky route can produce an optimal peak at ∆G_H* = ~0eV, where ∆G_H* is the free binding energy of hydrogen. The active species of H* has also been elucidated to be any adsorbed hydrogen, and not strictly H* adsorbed on weaker binding, atop sites. Tafel plots indicate that although electrochemical barriers vary with potential, the overall HER rate stays governed by the surface coverage of hydrogen. Lastly, we find that CO* and OH* adsorbate-adsorbate interactions can either hinder or promote HER by leaving only weaker binding sites to H*. Prior to presenting the findings, this thesis attempt at a short primer on the physical chemistry concepts behind computational catalysis, as well as the conceptual tools used in computational catalysis. The section is aimed at theoretical or experimental researchers with an interest in computational science and catalysis. This is in part because the technical jargon used herein may seem vague or less familiar to those not in the field of computational catalysis, such as the term 'free energetics', 'atomic orbitals', 'descriptor', 'scaling relations'. The reader is welcomed to bring themselves up to speed in the background and concepts section.

Download or read book Carbon Based Nanomaterials for Energy Conversion and Storage written by Jia-Nan Zhang and published by Springer Nature. This book was released on 2022-08-26 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book systematically summarizes the advanced development of carbon-based nanomaterials for electrochemical catalysis, and it is comprised of four sections. The first section discusses about the fundamental synthesis, characterization techniques, and catalytic effects on the energy conversion and storage mechanism. The second section elaborately reviews various types of electrocatalytic reactions on carbon-based materials and their performance. The third section focuses on batteries about carbon-based materials with different storage mechanism. And the last one, the following enlightenment in terms of theoretical development and experimental research is provided to the general readers: 1) Precise design and construction of local atomic and electronic structures at the interface of catalysts; 2) Selective activation and directed conversion of carbon-based energy-carrying molecules at the interface; 3) Interaction mechanism and regulation of catalyst solid surface interface properties under environment and external field. This book will be useful for researchers and students who are interested in carbon-based nanomaterials, electrochemical catalysts and energy storage.

Download or read book Quantum Mechanics for Scientists and Engineers written by David A. B. Miller and published by Cambridge University Press. This book was released on 2008-04-21 with total page 575 pages. Available in PDF, EPUB and Kindle. Book excerpt: If you need a book that relates the core principles of quantum mechanics to modern applications in engineering, physics, and nanotechnology, this is it. Students will appreciate the book's applied emphasis, which illustrates theoretical concepts with examples of nanostructured materials, optics, and semiconductor devices. The many worked examples and more than 160 homework problems help students to problem solve and to practise applications of theory. Without assuming a prior knowledge of high-level physics or classical mechanics, the text introduces Schrödinger's equation, operators, and approximation methods. Systems, including the hydrogen atom and crystalline materials, are analyzed in detail. More advanced subjects, such as density matrices, quantum optics, and quantum information, are also covered. Practical applications and algorithms for the computational analysis of simple structures make this an ideal introduction to quantum mechanics for students of engineering, physics, nanotechnology, and other disciplines. Additional resources available from www.cambridge.org/9780521897839.

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 Atomically Precise Electrocatalysts for Electrochemical Energy Applications written by Anuj Kumar and published by Springer Nature. This book was released on with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Development of Electrocatalysts and Their Microenvironments for Applications in Fuel Cells written by Jose Andres Zamora Zeledon and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Electrocatalysis plays a crucial role in a wide range of renewable and sustainable energy technologies, which are required to create a carbon-neutral or carbon-negative energy ecosystem, ultimately fostering the long-term prosperity of humankind. The oxygen reduction reaction (ORR) is key in electrochemical energy conversion and storage technologies such as fuel cells and metal-air batteries, which, for instance, have the potential to help decarbonize transportation and provide clean intermittent renewable energy storage. However, cheaper electrocatalyst materials with improved ORR activity, 4e--product selectivity, and stability are needed to deploy these promising technologies at a large scale. Anion exchange membrane fuel cells (AEMFCs) have emerged as a promising complementary alternative to the more mature proton exchange membrane fuel cells (PEMFCs) because the alkaline environment in AEMFCs allows for improved ORR kinetics and wider material stability compared to in the acidic conditions in PEMFCs. Moreover, diversifying ORR catalysts beyond conventional Pt-based materials is crucial for H2 FCs to achieve large scale deployment and thrive as a resilient and robust energy technology. Ag, which is two orders of magnitude cheaper than Pt, has emerged as a promising active, stable, and selective non-precious metal alkaline ORR catalyst. Moreover, Ag-bimetallics are an interesting class of materials for which density functional theory (DFT) modeling has predicted the possibility of intrinsically enhanced ORR kinetics. Ag-Cu, for instance, has already been shown to yield enhanced ORR active sites at certain surface compositions. Studying Ag-bimetallics in a well-controlled and systematic fashion is, therefore, crucial to developing material-property relationships that would aid in the design of optimal catalysts for the ORR and other important electrocatalytic reactions. In addition to catalyst material engineering, it is also important to study the electrolyte effects on electrocatalytic performance to design optimal electrochemical microenvironments. In this dissertation, I employ a wide range of complementary physical and electrochemical methods, in conjunction with DFT, to understand how to engineer high performing electrocatalysts. Specifically, I systematically synthesize, characterize, and test Ag-Pd and Ag-Mn alkaline ORR electrocatalysts, ultimately, establishing the fundamental material-property relationships attributed to the measured intrinsic catalyst performance as a function of composition and structure. The use of physical vapor deposition (PVD) is crucial for the systematic catalyst design and development in my work. Moreover, using PVD as a bridge between fundamental rotating disk electrode (RDE) and applied FC device studies, I systematically fabricate model ionomer-free Ag-Pd gas diffusion electrodes (GDEs) to investigate the performance of this material system in H2-O2 AEMFCs. Varying only the Ag:Pd alloy ratio, I find good agreement between the performance trends measured in the RDE and AEMFC configurations. In terms of electrocatalyst material engineering, in this work I develop Ag-based ORR electrocatalysts with tuned oxygen-adsorbate binding, affording state-of-the-art AEMFC performance. In addition, I also investigate the role of acid electrolyte anions on the ORR performance of Ag and Pd, as well as on the hydrogen and oxygen electrocatalysis performance of Pt. I find that performance varies as a function of electrolyte, that acid electrolyte anions effects are potential dependent, and that nitric acid affords improved electrolyte microenvironments conducive to improved performance compared to certain acids. By fundamentally understanding the interfacial processes responsible for the measured electrochemical performance, herein, I engineer high performing Ag-based ORR electrocatalysts and establish fundamental engineering principles to design optimal catalyst materials and catalyst--electrolyte microenvironments.

Download or read book Hierarchical Materials for Advanced Energy Storage written by Guanglin Xia and published by Frontiers Media SA. This book was released on 2020-12-21 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.

Download or read book Carbon Based Nanomaterials for Advanced Thermal and Electrochemical Energy Storage and Conversion written by Cheng-Te Lin and published by Elsevier. This book was released on 2019-07-20 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon Based Nanomaterials for Advanced Thermal and Electrochemical Energy Storage and Conversion presents a comprehensive overview of recent theoretical and experimental developments and prospects on carbon-based nanomaterials for thermal, solar and electrochemical energy conversion, along with their storage applications for both laboratory and industrial perspectives. Large growth in human populations has led to seminal growth in global energy consumption, hence fossil fuel usage has increased, as have unwanted greenhouse gases, including carbon dioxide, which results in critical environmental concerns. This book discusses this growing problem, aligning carbon nanomaterials as a solution because of their structural diversity and electronic, thermal and mechanical properties. Provides an overview on state-of-the-art carbon nanomaterials and key requirements for applications of carbon materials towards efficient energy storage and conversion Presents an updated and comprehensive review of recent work and the theoretical aspects on electrochemistry Includes discussions on the industrial production of carbon-based materials for energy applications, along with insights from industrial experts

Download or read book Metal Air Batteries written by Xin-bo Zhang and published by John Wiley & Sons. This book was released on 2019-02-11 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the research developments in the burgeoning field of metal-air batteries An innovation in battery science and technology is necessary to build better power sources for our modern lifestyle needs. One of the main fields being explored for the possible breakthrough is the development of metal-air batteries. Metal-Air Batteries: Fundamentals and Applications offers a systematic summary of the fundamentals of the technology and explores the most recent advances in the applications of metal-air batteries. Comprehensive in scope, the text explains the basics in electrochemical batteries and introduces various species of metal-air batteries. The author-a noted expert in the field-explores the development of metal-air batteries in the order of Li-air battery, sodium-air battery, zinc-air battery and Mg-O2 battery, with the focus on the Li-air battery. The text also addresses topics such as metallic anode, discharge products, parasitic reactions, electrocatalysts, mediator, and X-ray diffraction study in Li-air battery. Metal-Air Batteries provides a summary of future perspectives in the field of the metal-air batteries. This important resource: -Covers various species of metal-air batteries and their components as well as system designation -Contains groundbreaking content that reviews recent advances in the field of metal-air batteries -Focuses on the battery systems which have the greatest potential for renewable energy storage Written for electrochemists, physical chemists, materials scientists, professionals in the electrotechnical industry, engineers in power technology, Metal-Air Batteries offers a review of the fundamentals and the most recent developments in the area of metal-air batteries.

Download or read book Chemisorption and Reactivity on Supported Clusters and Thin Films written by R.M. Lambert and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heterogeneous catalysis provides the backbone of the world's chemical and oil industries. The innate complexity of practical catalytic systems suggests that useful progress should be achievable by investigating key aspects of catalysis by experimental studies on idealised model systems. Thin films and supported clusters are two promising types of model system that can be used for this purpose, since they mimic important aspects of the properties of practical dispersed catalysts. Similarly, appropriate theoretical studies of chemisorption and surface reaction clusters or extended slab systems can provide valuable information on the factors that underlie bonding and catalytic activity. This volume describes such experimental and theoretical approaches to the surface chemistry and catalytic behaviour of metals, metal oxides and metal/metal oxide systems. An introduction to the principles and main themes of heterogeneous catalysis is followed by detailed accounts of the application of modern experimental and theoretical techniques to fundamental problems. The application of advanced experimental methods is complemented by a full description of theoretical procedures, including Hartree-Fock, density functional and similar techniques. The relative merits of the various approaches are considered and directions for future progress are indicated.

Download or read book Hydrogen Storage Materials written by R. G. Barnes and published by . This book was released on 1988 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ames Laboratory, Iowa, USA

Download or read book Electrocatalysis for Energy Storage written by Nirala Singh and published by . This book was released on 2015 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efforts to improve the rhodium sulfide by incorporation of dopant atoms were not as effective as for the ruthenium sulfide compounds, as transition metals such as Fe, Co, Ni and Cu caused the formation of an inactive rhodium thiospinel phase, and platinum group metal dopants showed no improvement in the rhodium sulfide on a metal sulfide-area basis. The greatest improvements in the activity of the electrocatalyst come from smaller particle sizes of Rh17S 15 and Rh3S4 (increased dispersion), and minimization of inactive rhodium sulfide phases.

Download or read book Rational Design of Transition Metal Nitrogen Carbon Electrocatalysts for Oxygen Reduction Reaction written by Zhuang Liu and published by . This book was released on 2018 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT OF THE DISSERTATION Rational Design of Transition Metal-Nitrogen-Carbon Electrocatalysts for Oxygen Reduction Reaction by Zhuang Liu Doctor of Philosophy in Chemical Engineering University of California, Los Angeles, 2018 Professor Yunfeng Lu, Chair The harvest and conversion of energy is of crucial importance for human civilization. Today, the fast growth in energy consumption, together with the environmental problems caused by fossil fuel usage, calls for renewable and clean energy supply, such as solar, wind, geothermal, and tidal energy. However, such energies are not consistent in both time and location, bringing energy storage on request. Intensive research has been focused on the development of electrochemical energy storage (EES) devices. Among these EES devices, hydrogen fuel cells and metal-air batteries have attracted the special attention because of their high theoretical energy densities. Yet, one major issue lies in the sluggish oxygen reduction reaction (ORR) that takes place at the cathodes. For example, the theoretical voltage of a hydrogen-oxygen fuel cell is 1.23 V (standard condition). However, the voltage output obtained under a meaningful current density is only about 0.7 V, where the voltage loss is primarily caused by the overpotential in the cathodes. Developing efficient electro-catalysts, which can lower the overpotential of ORR, is indispensable for achieving high performance devices. The state-of-the-art ORR electro-catalysts are generally based on platinum, which is limited by cost and scarcity. Developing electro-catalysts based on earth abundant metal elements is critical for large-scale application of fuel cells and metal-air batteries. Among the non-precious-metal catalysts (NPMCs) explored in recent decades, pyrolyzed iron-nitrogen-carbon (Fe-N-C) catalysts is widely regarded as the most promising candidate for replacing platinum due to their high activity. However, the traditional method for preparing Fe-N-C catalysts involves high-temperature pyrolysis of the precursors, which is a highly complex and unpredictable process. As-prepared Fe-N-C catalysts usually contain mixed chemical phases (e.g., Fe-based nanoparticles, Fe-N coordination site and various nitrogen species), as well as carbon scaffolds with random morphology. Such complexity makes it difficult to identify the active site and control the porous structure. Though progress has been made in improving their performance through delicate selection of precursors, such process is largely based on test-and-trial method, shedding little light on the understanding of the material. In this dissertation, we designed a novel "post iron decoration" synthetic strategy towards efficient Fe-N-C catalysts, which de-convolutes the growth of iron and nitrogen species, enables the rational design of the catalyst structure, and provides a series of effective model materials for active site probing. Specifically, liquid iron penta-carbonyl was used to wet the surface of mesoporous N-doped carbon spheres (NMC), whose porous structure is determined by the template used for preparation. The obtained Fe(CO)5/NMC complex was then pyrolyzed to generate the Fe/NMC catalysts. Through comparative study and thorough material characterization, we demonstrated that the pyridinic-N of NMC anchors the Fe atoms to form Fe-Nx active sites during pyrolysis, while the graphitic-N remains ORR active. The excessive Fe atoms were aggregated forming fine nanoparticles, which were subsequently oxidized forming amorphous-iron oxide/iron crystal core-shell structure. All the composing elements of Fe/NMC catalysts are uniformly distributed on the NMC scaffold, whose porous structure is shown to be not affected by Fe decoration, guaranteeing the effective exposure of active sites. The best performing Fe/NMC catalysts exhibited a high half-wave potential of 0.862 V, which is close to that of the benchmark 40% Pt/C catalyst. Such high activity is primarily attributed to the Fe-Nx active sites in the catalysts. While the surface oxidized Fe crystallites though not being the major active site, is revealed to catalyze the reduction of HO2-, the 2e ORR product, facilitating the 4e reduction of oxygen. Finally, such synthetic strategy is successfully extended to prepare other Me-N-C materials. Based on the established understanding of the active sites, we then complexed the active Fe(CO)5 molecules with a N-rich metal-organic framework (ZIF-8) to form a precursor, which was subsequently pyrolyzed to form Fe-NC catalysts. During the pyrolysis, Fe(CO)5 reacts homogeneously with the ZIF-8 scaffold, leading to the formation of uniform distribution of Fe-related active sites on the N-rich porous carbon derived from ZIF-8. The zinc atoms in the crystalline structure of ZIF-8 serves as thermo-sacrificial template, resulting in the formation of hierarchical pores that provide abundant easily accessible ORR active sites. In virtue of these advantageous features, the best performing Fe-NC catalyst exhibited a high half-wave potential of 0.91 V in rotating disk electrode experiment in 0.1 M NaOH. Furthermore, zinc-air battery constructed with Fe-NC-900-M as the cathode catalyst exhibited high open-circuit voltage (1.5 V) and a peak power density of 271 mW cm-2, which outperforms those made with 40% Pt/C catalyst (1.48 V, 1.19 V and 242 mW cm-2), and most noble-metal free ORR catalysts reported so far. Finally, such a synthetic method is economic and easily-scalable, offering possibility for further activity and durability improvement.

Download or read book Recent Development in Energy Conversion Systems written by Sunday Olayinka Oyedepo and published by Frontiers Media SA. This book was released on 2024-03-15 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this industrial and technological age, energy plays a principal role in sustainable development. This is connected to issues regarding availability, production processes, utilization, and environmental impact. Due to the increased rate of population growth, the energy demand in the entire world is getting to the level that it may not be sustained in the nearest future if drastic action is not taken to address the situation, especially from research and development perspectives. "None of the millennium development goals (MDGs) can be completed without considerable improvements in the quality and quantity of energy services in developing countries," according to the United Nations Development Programme (UNDP). Based on this fact, UNDP is making efforts, especially in developing countries to ensure that people have access to sustainable sources of clean, reliable, and affordable energy since every aspect of human development is highly impacted by this vital resource.

Download or read book Micro nano materials for energy storage and conversion written by Jinlin Lu and published by Frontiers Media SA. This book was released on 2023-03-31 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nanocarbons for Advanced Energy Storage written by Xinliang Feng and published by John Wiley & Sons. This book was released on 2015-11-16 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this second volume in the first book series on nanocarbons for advanced applications the highly renowned series and volume editor has put together a top author team of internationally acclaimed experts on carbon materials. Divided into three major parts, this reference provides a current overview of the design, synthesis, and characterization of nanocarbons, such as carbon nanotubes, fullerenes, graphenes, and porous carbons for energy conversion applications. It covers such varied topics as electrocatalysts for oxygen reduction reactions in the different types of fuel cells, metal-air batteries and electrode materials for photovoltaic devices, as well as photocatalysts, electrocatalysts and photoelectrocatalysts for water splitting. Throughout, the authors highlight the unique aspects of nanocarbon materials in these fields, with a particular focus on the physico-chemical properties which lead to enhanced device performances.

Download or read book Nanomaterials for Electrocatalysis written by Thandavarayan Maiyalagan and published by Elsevier. This book was released on 2022-01-28 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanomaterials for Electrocatalysis provides an overview of the different types of nanomaterials, design principles and synthesis protocols used for electrocatalytic reactions. The book is divided into four parts that thoroughly describe basic principles and fundamental of electrocatalysis, different types of nanomaterials used, and their electrocatalytic applications, limitations and future perspectives. As electrochemical systems containing nanomaterials, with relevance to experimental situation, yield better results, this book highlights new information and findings. Provides an overview of nanomaterials applications for electrocatalytic processes, such as oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR) Provides information on the design and development of various nanomaterials appropriate for electrocatalytic applications Assesses the challenges of manufacturing nanomaterials at an industrial scale for electronic applications