Download or read book The Mechanism of Propane Ammoxidation Over the Ab Plane of the Mo V Te Nb O M1 Phase Probed by Density Functional Theory written by Junjun Yu and published by . This book was released on 2015 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: The selective ammoxidation of propane into acrylonitrile catalyzed by the bulk Mo-V-Te-Nb-O system received considerable attention because it is more environmentally benign than the current process of propylene ammoxidation and relies on a more abundant feedstock. This process consists of a series of elementary steps including propane oxidative dehydrogenation (ODH), ammonia and O2 activation, and N-insertion into C3 surface intermediates. However, the limited fundamental understanding of the reaction mechanism and the roles of the different cations have hindered the progress in further improving the activity and selectivity of these catalysts required for the commercial application. In this thesis, we present and discuss the results of the density functional theory (DFT) calculations performed to investigate the overall propane ammoxidation pathway employing the cluster models of the proposed selective and active sites present in the surface ab plane of the so-called M1 phase, which is the main catalytic phase present in the bulk mixed Mo-V-Te-Nb oxides. The activation energies for the oxidative dehydrogenation (ODH) of propane and sequentially formed intermediates (isopropyl, propene, and allyl) were calculated for different surface cation sites. Propane activation on V5=O was found to be the rate-limiting step (Ea = 1.2 eV), consistent with the current proposed reaction mechanism for propane activation on the bulk mixed Mo-V-Te-Nb oxides and the current understanding of V5+ as the active site for alkane activation present in V-based mixed oxides. Furthermore, a linear relationship was established between the H adsorption energy and the activation energy for H abstraction from various C3 intermediates, which is highly useful for predicting the energy barriers of H abstraction from C3 species based solely on H adsorption energy. The energy barriers of ammonia activation on different surface sites and NH insertion into the allyl species were investigated and discussed in terms of the hypothetical reaction pathway reported in the literature. These elementary reaction steps were indicated to be energetically barrier-less. The formation of acrylonitrile over Te=O as the H abstraction site from the surface absorbed precursor was found to be a barrier-less step. The overall reaction pathway was then explored using micro-kinetic models to study the selectivity of propane ammoxidation to acrylonitrile on the Mo-V-Te-Nb-O M1 phase. The calculated coverages of surface intermediates on Mo and V active sites from the micro-kinetic model indicated that NH is the dominant species on the surface as compared to surface O species which may explain why the M1 phase is so selective in transforming the gas-phase p-allyl intermediate into acrylonitrile as opposed to combustion products. This thesis reports the very first theoretical study of a complete mechanism of propane ammoxidation over surface ab planes of bulk mixed Mo-V-Te-Nb-O M1 phase. Improved understanding of the surface structure - reactivity relationships for propane ammoxidation to acrylonitrile over this model mixed metal oxide system gained in this research offers a possibility of not only molecular engineering of such mixed metal oxide catalysts for propane (amm)oxidation, but also fundamentally advancing the field of selective alkane (amm)oxidation over bulk mixed metal oxides.
Download or read book A Study of Propane and Propene Ammoxidation Over the Mo V Nb Te oxide System written by Johan Holmberg and published by . This book was released on 2006 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanostructured Catalysts written by Christian Hess and published by Royal Society of Chemistry. This book was released on 2011-07-22 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book gives a comprehensive up-to-date summary of the existing information on the structural/electronic properties, chemistry and catalytic properties of vanadium and molybdenum containing catalysts. It discusses the importance of nanoscience for the controlled synthesis of catalysts with functional properties and introduces the necessary background regarding surface properties and preparation techniques, leading from a textbook level to the current state of knowledge. Then follows an extensive survey and analysis of the existing open and patent literature - an essential knowledge source for the development of the new generation of partial oxidation catalysts. Important examples from current research on partial oxidation reactions are reviewed from experts in the field. The next chapter discusses the importance of 2- and 3-dimensional model systems for a fundamental understanding of the structure of transition metal oxide catalysts and its correlation to reactivity. Finally, an outlook on research opportunities within the area of partial oxidation reactions is presented.
Download or read book Metal Oxides in Heterogeneous Catalysis written by Jacques C. Vedrine and published by Elsevier. This book was released on 2018-01-11 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxides in Heterogeneous Catalysis is an overview of the past, present and future of heterogeneous catalysis using metal oxides catalysts. The book presents the historical, theoretical, and practical aspects of metal oxide-based heterogeneous catalysis. Metal Oxides in Heterogeneous Catalysis deals with fundamental information on heterogeneous catalysis, including reaction mechanisms and kinetics approaches.There is also a focus on the classification of metal oxides used as catalysts, preparation methods and touches on zeolites, mesoporous materials and Metal-organic frameworks (MOFs) in catalysis. It will touch on acid or base-type reactions, selective (partial) and total oxidation reactions, and enzymatic type reactions The book also touches heavily on the biomass applications of metal oxide catalysts and environmentally related/depollution reactions such as COVs elimination, DeNOx, and DeSOx. Finally, the book also deals with future trends and prospects in metal oxide-based heterogeneous catalysis. - Presents case studies in each chapter that provide a focus on the industrial applications - Includes fundamentals, key theories and practical applications of metal oxide-based heterogeneous catalysis in one comprehensive resource - Edited, and contributed, by leading experts who provide perspectives on synthesis, characterization and applications
Download or read book Nanotechnology in Catalysis 3 written by Bing Zhou and published by Springer Science & Business Media. This book was released on 2007-09-05 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume continues the tradition formed in Nanotechnology in Catalysis 1 and 2. As with those books, this one is based upon an ACS symposium. Some of the most illustrious names in heterogeneous catalysis are among the contributors. The book covers: Design, synthesis, and control of catalysts at nanoscale; understanding of catalytic reaction at nanometer scale; characterization of nanomaterials as catalysts; nanoparticle metal or metal oxides catalysts; nanomaterials as catalyst supports; new catalytic applications of nanomaterials.
Download or read book Urea SCR Technology for deNOx After Treatment of Diesel Exhausts written by Isabella Nova and published by Springer Science & Business Media. This book was released on 2014-03-14 with total page 715 pages. Available in PDF, EPUB and Kindle. Book excerpt: Urea-SCR Technology for deNOx After Treatment of Diesel Exhausts presents a complete overview of the selective catalytic reduction of NOx by ammonia/urea. The book starts with an illustration of the technology in the framework of the current context (legislation, market, system configurations), covers the fundamental aspects of the SCR process (catalysts, chemistry, mechanism, kinetics) and analyzes its application to useful topics such as modeling of full scale monolith catalysts, control aspects, ammonia injections systems and integration with other devices for combined removal of pollutants.
Download or read book Electron Energy Loss Spectroscopy in the Electron Microscope written by R.F. Egerton and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: to the Second Edition Since the first (1986) edition of this book, the numbers of installations, researchers, and research publications devoted to electron energy-loss spec troscopy (EELS) in the electron microscope have continued to expand. There has been a trend towards intermediate accelerating voltages and field-emission sources, both favorable to energy-loss spectroscopy, and sev eral types of energy-filtering microscope are now available commercially. Data-acquisition hardware and software, based on personal computers, have become more convenient and user-friendly. Among university re searchers, much thought has been given to the interpretation and utilization of near-edge fine structure. Most importantly, there have been many practi cal applications of EELS. This may reflect an increased awareness of the potentialities of the technique, but in many cases it is the result of skill and persistence on the part of the experimenters, often graduate students. To take account of these developments, the book has been extensively revised (over a period of two years) and more than a third of it rewritten. I have made various minor changes to the figures and added about 80 new ones. Except for a few small changes, the notation is the same as in the first edition, with all equations in SI units.
Download or read book Sol Gel Processing and Applications written by Y.A. Attia and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: During my professional career, I developed a strong interest in sol-gel technology, and worked on both xerogel and aerogel systems. My fascination with aerogels has driven me to explore their commercial potential, which is currently an important component of my company's business plan. Together with my co-workers, I have also worked on the preparation of controlled PZT and silica xerogels as well as thin film coatings of metals by the sol-gel technology, These experiences convinced me of the tremendous potentials of this technology. A conviction that is shared by many scientists, engineers, and business leaders around the globe. Many sol-gel derived products are already articles of commerce. However, to expand the commercial potential of sol-gel technology, two challenges must be met: (1) the quality of sol-gel derived products must continue to meet or exceed the quality of competing products, (2) the production cost of sol-gel products (specially aerogels) must continued to decline. A key to lowering the costs of sol-gel products is finding inexpensive precursors.
Download or read book Elements of Chemical Reaction Engineering written by H. Scott Fogler and published by Pearson Educación. This book was released on 1999 with total page 1006 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The fourth edition of Elements of Chemical Reaction Engineering is a completely revised version of the book. It combines authoritative coverage of the principles of chemical reaction engineering with an unsurpassed focus on critical thinking and creative problem solving, employing open-ended questions and stressing the Socratic method. Clear and organized, it integrates text, visuals, and computer simulations to help readers solve even the most challenging problems through reasoning, rather than by memorizing equations."--BOOK JACKET.
Download or read book Functional Oxides written by Duncan W. Bruce and published by John Wiley & Sons. This book was released on 2011-03-29 with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: Functional oxides have a wide variety of applications in the electronic industry. The discovery of new metal oxides with interesting and useful properties continues to drive much research in chemistry, physics, and materials science. In Functional Oxides five topical areas have been selected to illustrate the importance of metal oxides in modern materials chemistry: Noncentrosymmetric Inorganic Oxide Materials Geometrically Frustrated Magnetic Materials Lithium Ion Conduction in Oxides Thermoelectric Oxides Transition Metal Oxides - Magnetoresistance and Half-Metallicity The contents highlight structural chemistry, magnetic and electronic properties, ionic conduction and other emerging areas of importance, such as thermoelectricity and spintronics. Functional Oxides covers these complex concepts in a clear and accessible manner providing an excellent introduction to this broad subject area.
Download or read book Transition Metals in Coordination Environments written by Ewa Broclawik and published by Springer. This book was released on 2019-03-16 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the electronic properties of transition metals in coordination environments. These properties are responsible for the unique and intricate activity of transition metal sites in bio- and inorganic catalysis, but also pose challenges for both theoretical and experimental studies. Written by an international group of recognized experts, the book reviews recent advances in computational modeling and discusses their interplay using experiments. It covers a broad range of topics, including advanced computational methods for transition metal systems; spectroscopic, electrochemical and catalytic properties of transition metals in coordination environments; metalloenzymes and biomimetic compounds; and spin-related phenomena. As such, the book offers an invaluable resource for all researchers and postgraduate students interested in both fundamental and application-oriented research in the field of transition metal systems.
Download or read book Integrated 60GHz RF Beamforming in CMOS written by Yikun Yu and published by Springer Science & Business Media. This book was released on 2011-01-06 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: Integrated 60GHz RF Beamforming in CMOS describes new concepts and design techniques that can be used for 60GHz phased array systems. First, general trends and challenges in low-cost high data-rate 60GHz wireless system are studied, and the phased array technique is introduced to improve the system performance. Second, the system requirements of phase shifters are analyzed, and different phased array architectures are compared. Third, the design and implementation of 60GHz passive and active phase shifters in a CMOS technology are presented. Fourth, the integration of 60GHz phase shifters with other key building blocks such as low noise amplifiers and power amplifiers are described in detail. Finally, this book describes the integration of a 60GHz CMOS amplifier and an antenna in a printed circuit-board (PCB) package.
Download or read book Carbon Materials for Catalysis written by Philippe Serp and published by John Wiley & Sons. This book was released on 2009-02-04 with total page 603 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first comprehensive book covering all aspects of the use of carbonaceous materials in heterogeneous catalysis. It covers the preparation and characterization of carbon supports and carbon-supported catalysts; carbon surface chemistry in catalysis; the description of catalytic, photo-catalytic, or electro-catalytic reactions, including the development of new carbon materials such as carbon xerogels, aerogels, or carbon nanotubes; and new carbon-based materials in catalytic or adsorption processes. This is a premier reference for carbon, inorganic, and physical chemists, materials scientists and engineers, chemical engineers, and others.
Download or read book The Chemistry of Membranes Used in Fuel Cells written by Shulamith Schlick and published by John Wiley & Sons. This book was released on 2018-02-13 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Examines the important topic of fuel cell science by way of combining membrane design, chemical degradation mechanisms, and stabilization strategies This book describes the mechanism of membrane degradation and stabilization, as well as the search for stable membranes that can be used in alkaline fuel cells. Arranged in ten chapters, the book presents detailed studies that can help readers understand the attack and degradation mechanisms of polymer membranes and mitigation strategies. Coverage starts from fundamentals and moves to different fuel cell membrane types and methods to profile and analyze them. The Chemistry of Membranes Used in Fuel Cells: Degradation and Stabilization features chapters on: Fuel Cell Fundamentals: The Evolution of Fuel Cells and their Components; Degradation Mechanism of Perfluorinated Membranes; Ranking the Stability of Perfluorinated Membranes Used in Fuel Cells to Attack by Hydroxyl Radicals; Stabilization Mechanism of Perfluorinated Membranes by Ce(III) and Mn(II); Hydrocarbon Proton Exchange Membranes; Stabilization of Perfluorinated Membranes Using Nanoparticle Additives; Degradation Mechanism in Aquivion Perfluorinated Membranes and Stabilization Strategies; Anion Exchange Membrane Fuel Cells: Synthesis and Stability; In-depth Profiling of Degradation Processes in Nafion Due to Pt Dissolution and Migration into the Membrane; and Quantum Mechanical Calculations of the Degradation Mechanism in Perfluorinated Membranes. Brings together aspects of membrane design, chemical degradation mechanisms and stabilization strategies Emphasizes chemistry of fuel cells, which is underemphasized in other books Includes discussion of fuel cell performance and behavior, analytical profiling methods, and quantum mechanical calculations The Chemistry of Membranes Used in Fuel Cells is an ideal book for polymer scientists, chemists, chemical engineers, electrochemists, material scientists, energy and electrical engineers, and physicists. It is also important for grad students studying advanced polymers and applications.
Download or read book Zeolite Synthesis written by Mario L. Occelli and published by . This book was released on 1989 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is a complete progress report on the various aspects of zeolite synthesis on a molecular level. It provides many examples that illustrate how zeolites can be crystallized and what the important parameters are that control crystallization. Forty-two chapters cover such topics as: crystallization techniques; gel chemistry; crystal size and morphology; the role of organic compounds; and novel synthesis procedures. It offers a complete review of zeolite synthesis as well as the latest finding in this important field. Contains benchmark contributions from many notable pioneers in the field, including R.M. Barrer, H. Robson, and Robert Milton.
Download or read book Nanocatalysis in Ionic Liquids written by Martin H. G. Prechtl and published by John Wiley & Sons. This book was released on 2017-01-17 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Edited and written by renowned experts in the field, this is the first book to reflect the state of the art of nanocatalysis in ionic liquids. Divided into two core areas, the first part of the book describes the different classes of metal nanoparticles as well as their synthesis in ionic liquids, while the second focuses on such emerging issues as the application of such systems to energy and biomass conversion.
Download or read book Fundamentals of Natural Fibres and Textiles written by Md. Ibrahim H. Mondal and published by Woodhead Publishing. This book was released on 2021-03-20 with total page 817 pages. Available in PDF, EPUB and Kindle. Book excerpt: The textile industry is focused in its search for alternative green fibres with the aim of providing high-quality products which are fully recyclable and biodegradable. Natural textile materials from renewable sources play an increasingly important role in the industry due to their unique properties and functionality over synthetic fibres, as well as their sustainability. Fundamentals of Natural Fibres and Textiles covers all the fundamental and basic information about natural fibres and textiles. Many different fibres are covered from their origin, through processing, properties, and applications. The latest methods for characterisation and testing of natural fibres are all addressed with reference to cutting-edge industry trends. This uniquely comprehensive approach to the topic provides the ideal entry point to natural fibres for textile and clothing scientists, engineers, designers, researchers, students, and manufacturers of such products. - Explains the characteristics of natural fibres to show how they compare to synthetic fibres for a range of purposes - Provides an overview of the environmental impact of the processing of fibres and how this creates industrial waste - Covers a wide range of natural fibres in detail, from traditional silk and wool to electrospun biopolymers - Provides the latest updates on technologies for designing natural fibres and applying them to the development of new products
