Metal Support Interaction And Electrochemical Promotion Of Nano Structured Catalysts For The Reverse Water Gas Shift Reaction
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Metal Support Interaction And Electrochemical Promotion Of Nano Structured Catalysts For The Reverse Water Gas Shift Reaction
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Author : Christopher Panaritis
language : en
Publisher:
Release Date : 2021
Metal Support Interaction And Electrochemical Promotion Of Nano Structured Catalysts For The Reverse Water Gas Shift Reaction written by Christopher Panaritis and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
The continued release of fossil-fuel derived carbon dioxide (CO2) emissions into our atmosphere led humanity into a climate and ecological crisis. Converting CO2 into valuable chemicals and fuels will replace and diminish the need for fossil fuel-derived products. Through the use of a catalyst, CO2 can be transformed into a commodity chemical by the reverse water gas shift (RWGS) reaction, where CO2 reacts with renewable hydrogen (H2) to form carbon monoxide (CO). CO then acts as the source molecule in the Fischer-Tropsch (FT) synthesis to form a range of hydrocarbons to manufacture chemicals and fuels. While the FT synthesis is a mature process, the conversion of CO2 into CO has yet to be made commercially available due to the constraints associated with high reaction temperature and catalytic stability. Noble metal ruthenium (Ru) has been widely used for the RWGS reaction due to its high catalytic activity, however, several constraints hinder its practical use, associated with its high cost and its susceptibility to deactivation. The doping or bimetallic use of non-noble metals iron (Fe) and cobalt (Co) is an attractive option to lower material cost and tailor the selectivity of the CO2 conversion towards the RWGS reaction without compromising catalytic activity. Furthermore, employing nanostructured catalysts as nanoparticles is a viable solution to further lower the amount of metal used and utilize the highly active surface area of the catalyst. Dispersing nanoparticles on ionically conductive supports/solid electrolytes which contain species like O2−, H+, Na+, and K+, provide an approach to further enhance the reaction. This phenomenon is referred to as metal-support interaction (MSI), allowing for the ions to back spillover from the support and onto the catalyst surface. An in-situ approach referred to as Non-Faradaic Modification of catalytic activity (NEMCA), also known as electrochemical promotion of catalysis (EPOC) is used to in-situ control the movement of ionic species from the solid electrolyte to and away from the catalyst. Both the MSI and EPOC phenomena have been shown to be functionally equivalent, meaning the ionic species act to alter the work function of the catalyst by forming an effective neutral double layer on the surface, which in turn alters the binding energy of the reactant and intermediate species to promote the reaction. The main objective of this work is to develop a catalyst that is highly active and selective to the RWGS reaction at low temperatures (
Connecting Metal Support Interaction And Electrochemical Promotion Phenomena For Nano Structured Catalysts
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Author : Holly Dole
language : en
Publisher:
Release Date : 2016
Connecting Metal Support Interaction And Electrochemical Promotion Phenomena For Nano Structured Catalysts written by Holly Dole and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Effect Of Electrochemical Promotion And Metal Support Interaction On Catalytic Performance Of Nano Catalysts
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Author : Yasmine Hajar
language : en
Publisher:
Release Date : 2019
Effect Of Electrochemical Promotion And Metal Support Interaction On Catalytic Performance Of Nano Catalysts written by Yasmine Hajar and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.
In heterogeneous catalysis, promoting the activity of the catalytic metals is long known as an important method to make a process more efficient and viable. Noble metals have been promoted classically by a chemical coverage of an ionic solution on the surface of the catalyst or using inert support, e.g., silica or alumina, allowing an increase of the dispersion of the catalyst. Therefore, new methods of promotion needed to be better explored to improve the efficiency of metal and metal oxide catalysts. One way of enhancing the catalyst's activity is to disperse the noble metal at the nanoscale using an active type of support that is ion-conducting. Not only lattice ions can be exchanged with the surface of the nanoparticles but it can also engage in the oxidation reaction on the surface, resulting in what is known as metal-support interaction (MSI). Another method of improving the catalytic activity is to polarize the catalyst, allowing ions to migrate from a solid electrolyte to the gas-exposed surface, in a phenomenon known as electrochemical promotion of catalysis (EPOC). The change in the ions concentration on the surface would change the adsorption energy of the gaseous reactants and enhance or supress the catalytic rate. In this thesis, the effect of supporting nanoparticles of noble and non-noble metal (oxides) (Pt, Ru, Ir, Ni) was studied for the case of ionic and ionic-electronic conducting supports (CeO2, TiO2, YSZ). The enhancement in their catalytic rate was found and correlated to an electrochemical property, the exchange current density. Then, using isotopically-labeled oxygen, the oxygen exchange ability of the conductive oxides was evaluated when supporting Ir and Ru nanoparticles and correlated with the results from C3H8 isotopic oxidation reaction, which showed the extent of involvement of oxygen from the support as carried by the isotopically-labeled CO2 produced. Following this, electrochemical promotion of catalysis experiments were performed for different reactant/catalyst systems (C2H4 - Pt, Ru; C3H8 - Pt; CH4 - Pd, Ni9Pd). In the first system, the main outcome was the functional equivalence found for the MSI and EPOC effect in promoting the catalysts as experiments were performed at different temperatures, reactants partial pressures and polarization values. In the case of C3H8/Pt, the novel dispersion of Pt on an intermediate supporting layer (LSM/GDC) was found as a feasible method to obtain long stability of the catalyst while electrochemically promoting the rate of reaction. For CH4 oxidation, the polarization of the Pd nanoparticles showed continuous oxidation of the bulk of the catalyst resulting in a continuous increase of the catalytic rate. The Ni9Pd synthesized in a way to form a core/double-shell layer of Ni/Pd resulted in an enhanced catalytic rate and enhanced stability compared to stand-alone Pd. And lastly, to comprehend the ions' effect in the electrochemical promotion and the non-Faradaic nature of the phenomena, density-functional theory (DFT) modeling was used to demonstrate the increase of the heat of adsorption of reactants depending on their electronegative/positive nature.
Metal Oxide Based Nanostructured Electrocatalysts For Fuel Cells Electrolyzers And Metal Air Batteries
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Author : Teko Napporn
language : en
Publisher: Elsevier
Release Date : 2021-01-30
Metal Oxide Based Nanostructured Electrocatalysts For Fuel Cells Electrolyzers And Metal Air Batteries written by Teko Napporn and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-01-30 with Technology & Engineering categories.
Metal Oxide-Based Nanostructured Electrocatalysts for Fuel Cells, Electrolyzers, and Metal-Air Batteries is a comprehensive book summarizing the recent overview of these new materials developed to date. The book is motivated by research that focuses on the reduction of noble metal content in catalysts to reduce the cost associated to the entire system. Metal oxides gained significant interest in heterogeneous catalysis for basic research and industrial deployment. Metal Oxide-Based Nanostructured Electrocatalysts for Fuel Cells, Electrolyzers, and Metal-Air Batteries puts these opportunities and challenges into a broad context, discusses the recent researches and technological advances, and finally provides several pathways and guidelines that could inspire the development of ground-breaking electrochemical devices for energy production or storage. Its primary focus is how materials development is an important approach to produce electricity for key applications such as automotive and industrial. The book is appropriate for those working in academia and R&D in the disciplines of materials science, chemistry, electrochemistry, and engineering. Includes key aspects of materials design to improve the performance of electrode materials for energy conversion and storage device applications Reviews emerging metal oxide materials for hydrogen production, hydrogen oxidation, oxygen reduction and oxygen evolution Discusses metal oxide electrocatalysts for water-splitting, metal-air batteries, electrolyzer, and fuel cell applications
Encyclopedia Of Renewable Energy Sustainability And The Environment
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Author :
language : en
Publisher: Elsevier
Release Date : 2024-10-01
Encyclopedia Of Renewable Energy Sustainability And The Environment written by and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024-10-01 with Science categories.
Encyclopedia of Renewable Energy, Sustainability and the Environment, Four Volume Set comprehensively covers all renewable energy resources, including wind, solar, hydro, biomass, geothermal energy, and nuclear power, to name a few. In addition to covering the breadth of renewable energy resources at a fundamental level, this encyclopedia delves into the utilization and ideal applications of each resource and assesses them from environmental, economic, and policy standpoints. This book will serve as an ideal introduction to any renewable energy source for students, while also allowing them to learn about a topic in more depth and explore related topics, all in a single resource. Instructors, researchers, and industry professionals will also benefit from this comprehensive reference. Covers all renewable energy technologies in one comprehensive resource“/li> Details renewable energies’ processes, from production to utilization in a single encyclopedia Organizes topics into concise, consistently formatted chapters, perfect for readers who are new to the field Assesses economic challenges faced to implement each type of renewable energy Addresses the challenges of replacing fossil fuels with renewables and covers the environmental impacts of each renewable energy
Nanostructured Transition Metal Sulfide Catalysts For Electrochemical Water Splitting
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Author : Alex Wiltrout
language : en
Publisher:
Release Date : 2016
Nanostructured Transition Metal Sulfide Catalysts For Electrochemical Water Splitting written by Alex Wiltrout and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
With the worlds population steadily on the rise, there will continue to be an ever-increasing demand for energy. However, fossil fuels, which currently supply the world with an overwhelming portion of its energy needs, are quickly becoming depleted at a much faster rate than they are being generated. Most people use fossil fuels for their everyday energy needs, namely because compared to other alternative energy sources, it is cheaper and much more readily accessible. However, if one is looking to invest in a sustainable, long-term solution to the energy crisis that we currently face, these non-renewable energy sources are less than ideal. One possible solution to this problem is to begin using hydrogen as a fuel source instead. Hydrogen is an ideal alternative for a number of reasons, namely because it possesses the largest energy density by mass of any element, and that burning it produces no harmful byproducts, only water. The current industry standard for hydrogen production is primarily limited to production via steam-methane reformation and the water-gas shift reaction. However, these processes are not ideal for large-scale hydrogen production, and are detrimental to the environment because of the large amounts of CO and CO2 that are produced. One potentially cleaner alternative is proposed through electrochemical water splitting, whereby water is decomposed in hydrogen and oxygen. However, materials that catalyze these reactions are often quite rare and expensive, examples being Pt and IrO2. For this reason, the work hereafter aims to seek out new Earth-abundant materials, with a focus on transition metal sulfide systems, which can be used as catalysts to help catalyze the decomposition of water. Our work begins by investigating the catalytic activity of CuCo2S4 nanoparticles for the oxygen evolution reaction. Much of the focus insofar has been primarily concerned with transition metal oxide-based materials, however, metal sulfide systems are slowly gaining momentum. Those that do exist and have been tested for the oxygen evolution reaction (OER), often show moderate activity. By introducing additional elements into the system, we hope to further enhance the materials OER activity. Highly crystalline and nonagglomerated colloidal CuCo2S4 nanoparticles, which were previously inaccessible in the literature, were synthesized using low-temperature, solution-based synthetic routes. The CuCo2S4 nanoparticles were found to be highly active for OER under strongly alkaline conditions. Surface studies of the material suggest that mixed-metal sulfides, such as CuCo2S4, may in fact serve as precursors to oxides and/or hydroxides, which are likely the catalytically active species in solution. In addition to the work on the OER half reaction, a number of cobalt (Co3S4, CoS, Co9S8) and nickel sulfide (Ni3S2, -NiS, Ni9S8, Ni3S4) nanoparticle systems were investigated for use as potential hydrogen evolution reaction (HER) electrocatalysts. These materials were the target of this study because of their relatively low cost and high abundance within the Earths crust, as well as because they are know hydrodesulfurization (HDS) catalysts. Both HER and HDS rely upon a process by which hydrogen reversibly binds to the surface of a material. The hope was that one could then selectively target active HER catalysts, by identifying what materials are also good HDS catalysts. However, upon testing the cobalt and nickel sulfide nanoparticles, a correlation between HER and HDS could not be discerned.
Strong Metal Support Interactions
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Author : R. T. K. Baker
language : en
Publisher:
Release Date : 1986
Strong Metal Support Interactions written by R. T. K. Baker and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1986 with Science categories.
Strong Metal Support Interaction Of Pt Based Electrocatalysts With Transition Metal Oxides Nitrides Carbides For Oxygen Reduction Reaction
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Author : Min Chen
language : en
Publisher: OAE Publishing Inc.
Release Date : 2023-06-06
Strong Metal Support Interaction Of Pt Based Electrocatalysts With Transition Metal Oxides Nitrides Carbides For Oxygen Reduction Reaction written by Min Chen and has been published by OAE Publishing Inc. this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-06-06 with Technology & Engineering categories.
Nanostructured Non Precious Oxygen Reduction Reaction Catalysts For Electrochemical Energy Applications
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Author : Jason Wu
language : en
Publisher:
Release Date : 2015
Nanostructured Non Precious Oxygen Reduction Reaction Catalysts For Electrochemical Energy Applications written by Jason Wu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
Fuel cell and state of the art battery technologies share a common electrochemical reaction in their operation. The oxygen reduction reaction (ORR) is a key phenomenon for the efficient operation for both electrochemical devices. However, ORR often suffers from slow kinetics and requires electrocatalysts to speed-up the reaction to practical levels. The use of platinum based catalysts has long been considered the most effective solution in improving ORR kinetics; however, platinum is an extremely expensive metal and is limited in world supply. It is critical to find alternative, non-precious catalysts to replace platinum catalysts. Heat treated non-precious catalysts produced through high temperature pyrolysis of temperatures over 600 °C are promising class of materials, showing high catalytic activity and stability in both acidic and alkaline conditions. However, heat treated non-precious catalysts do not match platinum based catalysts in terms of stability and activity. Furthermore, the active sites of heat treated non-precious catalysts are still under debate. In the present work, non-precious carbon catalysts were synthesized via pyrolysis of carbon in the presence of nitrogen and a transition metal then evaluated and characterized. Iron is chosen as the transition metal for all of the experiments as it is naturally abundant, relatively safe, and displays the highest activity amongst transition metals in this application. In fact, iron displays the highest redox potential which has been noted to be related to the binding of dioxygen species. A number of different catalysts were synthesized then studied by varying the synthesis conditions and precursors employed to increase the activity of non-precious carbon catalysts. First, a new nitrogen rich ligand is synthesized to be used as the nitrogen source during pyrolysis. This ligand will chelate with iron in the system and thus will help prevent agglomeration of iron particles during pyrolysis, resulting in many isolated active sites. The ratios of iron to ligand were varied and the affects of varying the mass of iron in the system on catalytic activity was studied. Following this work, support-less catalysts focusing on employing one-dimensional nanofiber structures were synthesized using polyacrylonitrile as the basis of producing one-dimensional nanofibers. One-dimensional nanofibrous electrocatalysts were synthesized via electrospinning a solution of polyacrylonitrile in DMF. Iron was added into the solution as well to ensure the electrospun fibers were well impregnated with iron. The resulting nanofibers were then pyrolyzed and the catalysts were evaluated and characterized. The results that followed indicated that surface area and porosity of catalysts plays a significant role in obtaining highly active catalysts. Highly porous carbon catalysts were then synthesized, evaluated, and characterized as a result of this discovery. These catalysts were produced via electrospinning an emulsion of polyacrylonitrile and fumed silica particles. After pyrolysis, these particles were removed by treating the catalyst with HF acid. The results of the work completed have shown that it is possible to produce non-precious catalysts that can replace platinum, bringing us a step closer to full commercialization of renewable energy devices.
Rational Design And Synthesis Of Inorganic Nanostructures For Tandem Catalysis And Co2 Conversion
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Author : Chenlu Xie
language : en
Publisher:
Release Date : 2018
Rational Design And Synthesis Of Inorganic Nanostructures For Tandem Catalysis And Co2 Conversion written by Chenlu Xie and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
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.