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Rational Design Of Electrocatalysts With Enhanced Catalytic Performance In Energy Conversion
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Book Synopsis Rational Design of Electrocatalysts with Enhanced Catalytic Performance in Energy Conversion by : Changlin Zhang
Download or read book Rational Design of Electrocatalysts with Enhanced Catalytic Performance in Energy Conversion written by Changlin Zhang and published by . This book was released on 2016 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: To provide alternative electrocatalysts for energy conversion and storage applications, the catalysts development including materials design, synthesis and growth mechanism, electrochemical diagnose, and reaction mechanism have been investigated and analyzed. Based on the research results in this dissertation, 8 first-authored journal papers have been published/submitted or in preparation. The research results here demonstrate a generic solid-state chemistry method for mass production of platinum group metal/alloy nanoparticles with size/shape/composition control, which could be used in multiple applications such as ammonia electro oxidation, oxygen reduction reaction, hydrazine decomposition, and carbon monoxide preferential oxidations. A highly ordered mesoporous carbon-based nanostructures as non-noble metal catalysts were also studied for oxygen reduction reaction and water splitting. To better understand the surface and interface behavior of platinum alloy catalyst under realistic reaction conditions, in-situ transmission electron microscopy was applied to dynamically investigate the real-time structure evolutions. The findings here also provide insights for establishing realistic structures-properties-applications relationships for materials science, catalysis and electrochemistry.
Book Synopsis Design Principle on Carbon Nanomaterials Electrocatalysts for Energy Storage and Conversion by : Zhenghang Zhao
Download or read book Design Principle on Carbon Nanomaterials Electrocatalysts for Energy Storage and Conversion written by Zhenghang Zhao and published by . This book was released on 2017 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: We are facing an energy crisis because of the limitation of the fossil fuel and the pollution caused by burning it. Clean energy technologies, such as fuel cells and metal-air batteries, are studied extensively because of this high efficiency and less pollution. Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential in the process of energy storage and conversion, and noble metals (e.g. Pt) are needed to catalyze the critical chemical reactions in these devices. Functionalized carbon nanomaterials such as heteroatom-doped and molecule-adsorbed graphene can be used as metal-free catalysts to replace the expensive and scarce platinum-based catalysts for the energy storage and conversion. Traditionally, experimental studies on the catalytic performance of carbon nanomaterials have been conducted extensively, however, there is a lack of computational studies to guide the experiments for rapid search for the best catalysts. In addition, theoretical mechanism and the rational design principle towards ORR and OER also need to be fully understood. In this dissertation, density functional theory calculations are performed to calculate the thermodynamic and electrochemical properties of heteroatom-doped graphene and molecule-adsorbed graphene for ORR and OER. Gibb's free energy, overpotential, charge transfer and edge effect are evaluated. The charge transfer analysis show the positive charges on the graphene surface caused by the heteroatom, hetero-edges and the adsorbed organic molecules play an essential role in improving the electrochemical properties of the carbon nanomaterials. Based on the calculations, design principles are introduced to rationally design and predict the electrochemical properties of doped graphene and molecule-adsorbed graphene as metal-free catalysts for ORR and OER. An intrinsic descriptor is discovered for the first time, which can be used as a materials parameter for rational design of the metal-free catalysts with carbon nanomaterials for energy storage and conversion. The success of the design principle provides a better understanding of the mechanism behind ORR and OER and a screening approach for the best catalyst for energy storage and conversion.
Book Synopsis Computational Electrochemistry by : S. Paddison
Download or read book Computational Electrochemistry written by S. Paddison and published by The Electrochemical Society. This book was released on 2015-12-28 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Durable Fuel Cell Electrocatalysts for Energy Conversion by : Zishuai Zhang
Download or read book Durable Fuel Cell Electrocatalysts for Energy Conversion written by Zishuai Zhang and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Electrocatalysts play an important avenue in clean and efficient energy conversion. Of the many electrocatalytic processes, the oxygen reduction reaction (ORR) attracts increasing attention due to its widespread importance in electrochemical cells. One of the most important applications is in proton-exchange membrane fuel cells (PEMFCs), which are considered as a promising power generation system because of its low operating temperature (70-90 ̊C), sustainable energy sources (hydrogen) and high energy efficiency. ORR is a key half reaction that takes place at the cathode with sluggish kinetics and requires noble metal (e.g. platinum)-based electrocatalysts to increase the reaction rate to attain practically usable levels. High cost and poor durability are major drawbacks of the commercial platinum on carbon (Pt/C) catalyst, and the corrosion of the carbon supports is considered one of the main reasons for the loss of expensive Pt, resulting in loss of performance of PEMFC. Therefore, more corrosion resistant, electrochemically stable and low-cost supports are highly desired for PEMFCs’ improved performance.Methanol oxidation reaction (MOR) is an anodic half reaction occurs at anodes of methanol fuel cells. Pt/C catalyst is also commonly used for that reaction. This thesis attempts to rationally design and synthesize various different nanostructured alternatives to carbon black for ORR and MOR. Graphene, a high conductive and stable two-dimensional carbon support, was successfully exfoliated electrochemically with little defects. Platinum (Pt) nanoparticles were deposited on graphene via double-pulse deposition technique. The catalyst was demonstrated to be highly efficient for MOR with a 920 mA/mg forward current density.Durable carbon nanotube (CNT) microspheres were synthesized through a facile and scalable ultrasonic bonding method without any binder or surfactant. The CNT microspheres with electrodeposited Pt were showcased as efficient ORR catalyst supports which showed no degradation after 12, 000 cycles (26.6 h). Furthermore, a soluble acicular calcium carbonate (aragonite, diameter 100 nm; length 800 nm) was used to created connected porosity in the microspheres to improve the mass transfer as the thickness increases. As for the ORR catalysis performance, the Pt decorated microspheres with macropores was 3.4 times higher (specific activity at 0.9V vs RHE) than non-macroporous microspheres with the identical Pt loading.Besides carbon-based supports, TiC was investigated as a potential carbon alternative due to its metallic electrical conductivity and excellent corrosion resistance. A cobalt oxide shell with high ORR activity was deposited onto TiC to improve its stability at high potential. We demonstrated that the oxide anchored Pt on TiC catalysts exhibited excellent durability (~100% catalytic activity remained at 0.1M KOH, and ~92% catalytic activity remained at 0.1M HClO4 after 16.7 h) compared to the Pt/C (~50% remained in both alkaline and acidic solutions). As assessed by transmission electron microscope (TEM), no significant Pt detachment or agglomeration was observed in oxide anchored catalysts, while heavily agglomeration has occurred to Pt/C.Hematene, two-dimensional layer of hematite (Fe2O3), has recently been exfoliated by means of liquid exfoliation. As the biodegradable metal, Fe-based materials attracts lots of attentions due to their ability to be entirely dissolved and cleared from the body. Electronics comprised of biodegradable metals can be programmed to degrade after the implantation. Here, we fabricated potentially biodegradable electrodes by using Au and hematene for glucose oxidation. It showed 9.5 mA/mgAu oxidation current density at the potential of 0.6V (vs. RHE), and high stability during the continuous cell cycling. Additionally, the prepared catalyst exhibited short response time and linear calibration range"--
Book Synopsis Rational Design of Solar Cells for Efficient Solar Energy Conversion by : Alagarsamy Pandikumar
Download or read book Rational Design of Solar Cells for Efficient Solar Energy Conversion written by Alagarsamy Pandikumar and published by John Wiley & Sons. This book was released on 2018-10-09 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: An interdisciplinary guide to the newest solar cell technology for efficient renewable energy Rational Design of Solar Cells for Efficient Solar Energy Conversion explores the development of the most recent solar technology and materials used to manufacture solar cells in order to achieve higher solar energy conversion efficiency. The text offers an interdisciplinary approach and combines information on dye-sensitized solar cells, organic solar cells, polymer solar cells, perovskite solar cells, and quantum dot solar cells. The text contains contributions from noted experts in the fields of chemistry, physics, materials science, and engineering. The authors review the development of components such as photoanodes, sensitizers, electrolytes, and photocathodes for high performance dye-sensitized solar cells. In addition, the text puts the focus on the design of material assemblies to achieve higher solar energy conversion. This important resource: Offers a comprehensive review of recent developments in solar cell technology Includes information on a variety of solar cell materials and devices, focusing on dye-sensitized solar cells Contains a thorough approach beginning with the fundamental material characterization and concluding with real-world device application. Presents content from researchers in multiple fields of study such as physicists, engineers, and material scientists Written for researchers, scientists, and engineers in university and industry laboratories, Rational Design of Solar Cells for Efficient Solar Energy Conversion offers a comprehensive review of the newest developments and applications of solar cells with contributions from a range of experts in various disciplines.
Book Synopsis Multi-functional Electrocatalysts by : Viswanathan S Saji
Download or read book Multi-functional Electrocatalysts written by Viswanathan S Saji and published by Royal Society of Chemistry. This book was released on 2024-08-28 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multi-functional electrocatalysts are highly unique in that they display features that include the presence of multiple active sites that can simultaneously catalyse two or more different electrochemical reactions. They are particularly crucial for solving several pressing challenges and consequently are a priority in developing contemporary sustainable energy conversion and storage systems, such as fuel cells, metal–air batteries and electrolysers for green hydrogen production. This book will serve as a valuable reference for graduate students, researchers, and industrial practitioners working on electrochemical energy storage and conversion, electrocatalysis, materials chemistry and green hydrogen technologies.
Book Synopsis Atomically Precise Electrocatalysts for Electrochemical Energy Applications by : Anuj Kumar
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:
Book Synopsis Rational Design of Transition Metal-Nitrogen-Carbon Electrocatalysts for Oxygen Reduction Reaction by : Zhuang Liu
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.
Book Synopsis Fabrication of Metal–Organic Framework Derived Nanomaterials and Their Electrochemical Applications by : Wei Xia
Download or read book Fabrication of Metal–Organic Framework Derived Nanomaterials and Their Electrochemical Applications written by Wei Xia and published by Springer. This book was released on 2018-04-03 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis systematically introduces readers to a new metal-organic framework approach to fabricating nanostructured materials for electrochemical applications. Based on the metal-organic framework (MOF) approach, it also demonstrates the latest ideas on how to create optimal MOF and MOF-derived nanomaterials for electrochemical reactions under controlled conditions. The thesis offers a valuable resource for researchers who want to understand electrochemical reactions at nanoscale and optimize materials from rational design to achieve enhanced electrochemical performance. It also serves as a useful reference guide to fundamental research on advanced electrochemical energy storage materials and the synthesis of nanostructured materials.
Book Synopsis Electrocatalysts for Fuel Cells and Hydrogen Evolution by : Abhijit Ray
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.
Book Synopsis The Rational Design of Selective Electrocatalysts for Renewable Energy Devices by : Daniel F. Abbott
Download or read book The Rational Design of Selective Electrocatalysts for Renewable Energy Devices written by Daniel F. Abbott and published by . This book was released on 2015 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rational design of electrocatalysts is paramount to the development of electrochemical devices. In particular, modifications to the structure and electronic properties of a particular catalyst can have a strong influence on the activity and selectivity towards various electrochemical reactions or pathways. In many cases this can lead to a particular reaction pathway being opened or closed, the formation of intermediates being stabilized or inhibited, the adsorption of poisonous species being mitigated, or the removal of poisonous species being promoted. In the this dissertation the design and characterization of catalysts for electrochemical devices (fuel cells, electrolyzers, and hydrogen pumps) will be discussed with regards to tailoring the selectivity in order to promote or inhibit certain electrochemical reactions. The electrochemical reactions of primary interest will include the methanol oxidation reaction (MOR), the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen oxidation reaction (HOR).
Book Synopsis Rational Design and Synthesis of Inorganic Nanostructures for Tandem Catalysis and CO2 Conversion by : Chenlu Xie
Download or read book Rational Design and Synthesis of Inorganic Nanostructures for Tandem Catalysis and CO2 Conversion written by Chenlu Xie and published by . This book was released on 2018 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: The subject of this dissertation focuses on the design and synthesis of new catalysts with well-defined structures and superior performance to meet the new challenges in heterogenous catalysis. The past decade has witness the development of nanoscience as well as the inorganic catalysts for industrial applications, however there are still fundamental challenges and practical need for catalysis. Specifically, it is desirable to have the ability to selectivity produce complex molecules from simple components. Another great challenge faced by the modern industry is being environmentally friendly, and going for a carbon neutral economy would require using CO2 as feedstock to produce valuable products. The work herein focuses on the design and synthesis of inorganic nanocrystal catalysts that address these challenges by achieving selective and sequential chemical reactions and conversion of CO2 to valuable products. Chapter 1 introduces the development of heterogenous catalysis and the colloidal synthesis of metal nanoparticles catalysts with well-controlled structure. Tremendous efforts have been devoted to understanding the nucleation and growth process in the colloidal synthesis and developing new methods to produce metal nanoparticles with controlled sizes, shapes, composition. These well-defined catalytic system shows promising catalytic performance, which can be modulated by their structure (size, shape, compositions and the metal-oxide interfaces). The chapters hereafter explore the synthesis of new catalysts with controlled structures for catalysis. Chapter 2 presents the design and synthesis of a three dimensional (3D) nanostructured catalysts CeO2-Pt@mSiO2 with dual metal-oxide interfaces to study the tandem hydroformylation reaction in gas phase, where CO and H2 produced by methanol decomposition (catalyzed by CeO2-Pt interface) were reacted with ethylene to selectively yield propyl aldehyde (catalyzed by Pt-SiO2 interface). With the stable core-shell architecture and well-defined metal-oxide interfaces, the origin of the high propyl aldehyde selectivity over ethane, the dominant byproduct in conventional hydroformylation, was revealed by in-depth mechanism study and attributed to the synergybetween the two sequential reactions and the altered elementary reaction steps of the tandem reaction compared to the single-step reaction. The effective production of aldehyde through the tandem hydroformylation was also observed on other light olefin system, such as propylene and 1-butene. Chapter 3 expands the strategy of tandem catalysis into conversion of CO2 with hydrogen to value-added C2-C4 hydrocarbons, which is a major pursuit in clean energy research. Another well-defined 3D catalyst CeO2–Pt@mSiO2–Co was designed and synthesized, and CO2 was converted to C2-C4 hydrocarbons with 60% selectivity on this catalyst via reverse water gas shift reaction and subsequent Fischer–Tropsch process. In addition, the catalysts is stable and shows no obvious deactivation over 40 h. The successful production of C2−C4 hydrocarbons via a tandem process on a rationally designed, structurally well-defined catalyst demonstrates the power of sophisticated structure control in designing nanostructured catalysts for multiple-step chemical conversions. Chapter 4 turns to electrochemistry and apply the precision in catalyst structural design to the development of electrocatalysts for CO2 reduction. Herein, atomic ordering of bimetallic nanoparticles were synthetically tuned, from disordered alloy to ordered intermetallic, and it showed that this atomic level control over nanocrystal catalysts could give significant performance benefits in electrochemical CO2 reduction to CO. Atomic-level structural investigations revealed the atomic gold layers over the intermetallic core to be sufficient for enhanced catalytic behavior, which is further supported by DFT analysis.
Book Synopsis Metal Organic Frameworks and Their Derivatives for Energy Conversion and Storage by : Cao Guan
Download or read book Metal Organic Frameworks and Their Derivatives for Energy Conversion and Storage written by Cao Guan and published by Elsevier. This book was released on 2024-01-19 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Organic Frameworks and Their Derivatives for Energy Conversion and Storage comprehensively covers the updated design and synthesis of metal organic frameworks (MOFs) and their derived materials, together with their applications in electrochemical energy conversion and storage. It starts with a systematic description of the rational structure design and facile fabrication methods of MOF-based materials and various MOF derivatives. Then representative examples of MOFs and MOF-derived materials used for solar water splitting, electrocatalysis, batteries and supercapacitors are demonstrated. Finally, developing trends, such as integrating MOFs with other smart materials and emerging 3D printing technology, is also covered. This book is suitable for a wide readership in material science, chemical science, energy field and engineering. Reviews the current research directions of metal-organic frameworks and their derived materials for electrochemical energy storage and conversion technologies Discusses synthesis and design strategies of metal-organic framework derived materials Focuses on the material-structure-property relationship and the impact towards the improved performance of metal-organic framework materials
Book Synopsis Sustainable Materials and Green Processing for Energy Conversion by : Kuan Yew Cheong
Download or read book Sustainable Materials and Green Processing for Energy Conversion written by Kuan Yew Cheong and published by Elsevier. This book was released on 2021-10-01 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sustainable Materials and Green Processing for Energy Conversion provides a concise reference on green processing and synthesis of materials required for the next generation of devices used in renewable energy conversion and storage. The book covers the processing of bio-organic materials, environmentally-friendly organic and inorganic sources of materials, synthetic green chemistry, bioresorbable and transient properties of functional materials, and the concept of sustainable material design. The book features chapters by worldwide experts and is an important reference for students, researchers, and engineers interested in gaining extensive knowledge concerning green processing of sustainable, green functional materials for next generation energy devices. Additionally, functional materials used in energy devices must also be able to degrade and decompose with minimum energy after being disposed of at their end-of-life. Environmental pollution is one of the global crises that endangers the life cycles of living things. There are multiple root causes of this pollution, including industrialization that demands a huge supply of raw materials for the production of products related to meeting the demands of the Internet-of-Things. As a result, improvement of material and product life cycles by incorporation of green, sustainable principles is essential to address this challenging issue. Offers a resourceful reference for readers interested in green processing of environmentally-friendly and sustainable materials for energy conversion and storage devices Focuses on designing of materials through green-processing concepts Highlights challenges and opportunities in green processing of renewable materials for energy devices
Book Synopsis Rational Design Strategies for Oxide Oxygen Evolution Electrocatalysts by : Wesley Terrence Hong
Download or read book Rational Design Strategies for Oxide Oxygen Evolution Electrocatalysts written by Wesley Terrence Hong and published by . This book was released on 2016 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding and mastering the kinetics of oxygen electrocatalysis is instrumental to enabling solar fuels, fuel cells, electrolyzers, and metal-air batteries. Non-precious transition metal oxides show promise as cost-effective materials in such devices. Leveraging the wealth of solid-state physics understanding developed for this class of materials in the past few decades, new theories and strategies can be explored for designing optimal catalysts. This work presents a framework for the rational design of transition-metal perovskite oxide catalysts that can accelerate the development of highly active catalysts for more efficient energy storage and conversion systems. We describe a method for the synthesis of X-ray emission, absorption, and photoelectron spectroscopy data to experimentally determine the electronic structure of oxides on an absolute energy scale, as well as extract key electronic parameters associated with the material. Using this approach, we show that the charge-transfer energy - a parameter that captures the energy configuration of oxygen and transition-metal valence electrons - is a central descriptor capable of modifying both the oxygen evolution kinetics and mechanism. Its role in determining the absolute band energies of a catalyst can rationalize the differences in the electron-transfer and proton-transfer kinetics across oxide chemistries. Furthermore, we corroborate that the charge-transfer energy is one of the most influential parameters on the oxygen evolution reaction through a statistical analysis of a multitude of structure-activity relationships. The quantitative models generated by this analysis can then be used to rapidly screen oxide materials across a wide chemical space for highthroughput materials discovery.
Book Synopsis Nanocarbons for Advanced Energy Storage by : Xinliang Feng
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.
Book Synopsis Design and Development of Electrocatalysts and Their Microenvironments for Applications in Fuel Cells by : Jose Andres Zamora Zeledon
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.
