Download or read book The Effects of Surface Structure on Catalytic Reactions written by Keith Ryan McCrea and published by . This book was released on 2001 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Surface Structure on Catalytic Reactions written by Keith Ryan McCrea and published by . This book was released on 2001 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Surface Structure on Catalytic Reactions written by and published by . This book was released on 2001 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the results discussed above, it is clear that Sum Frequency Generation (SFG) is a unique tool that allows the detection of vibrational spectra of adsorbed molecules present on single crystal surfaces under catalytic reaction conditions. Not only is it possible to detect active surface intermediates, it is also possible to detect spectator species which are not responsible for the measured turnover rates. By correlating high-pressure SFG spectra under reaction conditions and gas chromatography (GC) kinetic data, it is possible to determine which species are important under reaction intermediates. Because of the flexibility of this technique for studying surface intermediates, it is possible to determine how the structures of single crystal surfaces affect the observed rates of catalytic reactions. As an example of a structure insensitive reaction, ethylene hydrogenation was explored on both Pt(111) and Pt(100). The rates were determined to be essentially the same. It was observed that both ethylidyne and di-[sigma] bonded ethylene were present on the surface under reaction conditions on both crystals, although in different concentrations. This result shows that these two species are not responsible for the measured turnover rate, as it would be expected that one of the two crystals would be more active than the other, since the concentration of the surface intermediate would be different on the two crystals. The most likely active intermediates are weakly adsorbed molecules such as [pi]-bonded ethylene and ethyl. These species are not easily detected because their concentration lies at the detection limit of SFG. The SFG spectra and GC data essentially show that ethylene hydrogenation is structure insensitive for Pt(111) and Pt(100). SFG has proven to be a unique and excellent technique for studying adsorbed species on single crystal surfaces under high-pressure catalytic reactions. Coupled with kinetic data obtained from gas chromatography measurements, it can give much insight into how the structure of a single crystal surface affects the chemistry of a catalytic reaction by detecting surface species under reaction conditions.
Download or read book Catalytic Reactions of Hydrocarbons on Platinum Single Crystal Stepped Surfaces written by Donald Willaim Blakely and published by . This book was released on 1976 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Catalysis written by Bruce C. Gates and published by Academic Press. This book was released on 2001-05-14 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface science emerged in the 1960s with the development of reliable ultrahigh vacuum apparatus, providing exact structures of surfaces of metal single crystals, information about their compositions, and relationships between surface structure and composition and catalytic reaction rates. Catalysis, the acceleration of a chemical reaction by a catalyst (substance), provided much of the driving force for the early development of surface science. As surface science continues its rapid development, this book illustrates how it is still driven by the challenges of catalysis and how both theory and scanning tunneling microscopy have forcefully emerged as essential tools. It is also evident how surface science continues to serve as the foundation of catalytic science. This is a compendium written by leading surface scientists presenting an incisive assessment of up-to-date theoretical and experimental results constituting the foundation of fundamental understanding of surface catalysis. This paperback.
Download or read book Catalysis by Materials with Well Defined Structures written by Zili Wu and published by Academic Press. This book was released on 2015-03-26 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysis by Materials with Well-Defined Structures examines the latest developments in the use of model systems in fundamental catalytic science. A team of prominent experts provides authoritative, first-hand information, helping readers better understand heterogeneous catalysis by utilizing model catalysts based on uniformly nanostructured materials. The text addresses topics and issues related to material synthesis, characterization, catalytic reactions, surface chemistry, mechanism, and theoretical modeling, and features a comprehensive review of recent advances in catalytic studies on nanomaterials with well-defined structures, including nanoshaped metals and metal oxides, nanoclusters, and single sites in the areas of heterogeneous thermal catalysis, photocatalysis, and electrocatalysis. Users will find this book to be an invaluable, authoritative source of information for both the surface scientist and the catalysis practitioner - Outlines the importance of nanomaterials and their potential as catalysts - Provides detailed information on synthesis and characterization of nanomaterials with well-defined structures, relating surface activity to catalytic activity - Details how to establish the structure-catalysis relationship and how to reveal the surface chemistry and surface structure of catalysts - Offers examples on various in situ characterization instrumental techniques - Includes in-depth theoretical modeling utilizing advanced Density Functional Theory (DFT) methods
Download or read book Catalytic Reaction Mechanisms The Role of Surface Structure and Composition Proceedings of a Symposium at the Annual Meeting of the Materials Research Society Held at Boston Massachusetts on 14 16 November 1983 written by G. B. Fisher and published by . This book was released on 1984 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains a large majority of the invited and contributed papers presented at the three day symposium. Catalytic Reaction Mechanisms: The Role of Surface Structure and Composition, which took place at the annual Materials Research Society Meeting in Boston, Massachusetts, November 14-16, 1983. This conference was organized in response to the recent growth in basic research on the catalytic reactivity of chemically and structurally modified surfaces. The eight invited and their eight contributed talks were given on experimental and theoretical research which included comment on the following issues in surface science and heterogeneous catalysis: the effect of additives on surface reactions, short-range versus long-range effects on reactions by promoters or poisons, ensemble size of active sites, strong and weak metal-support interactions identification of surface reaction intermediates, particle size effects, and the reconstruction of metal and alloy surfaces. In general, characterizing the composition or structure of a particular surface or catalyst was not sufficient for a successful presentation at this conference; it was necessary to go further and demonstrate the effect of a surface compositional or structural variable on a surface reaction. By the end of the symposium several observations were inescapable concerning research discussed at the meeting. The technological importance of metal-oxide catalysts was made clear and was contrasted with the relative dearth of surface science studies in this area.
Download or read book Introduction to Surface Chemistry and Catalysis written by Gabor A. Somorjai and published by John Wiley & Sons. This book was released on 2010-06-08 with total page 804 pages. Available in PDF, EPUB and Kindle. Book excerpt: Now updated-the current state of development of modern surface science Since the publication of the first edition of this book, molecular surface chemistry and catalysis science have developed rapidly and expanded into fields where atomic scale and molecular information were previously not available. This revised edition of Introduction to Surface Chemistry and Catalysis reflects this increase of information in virtually every chapter. It emphasizes the modern concepts of surface chemistry and catalysis uncovered by breakthroughs in molecular-level studies of surfaces over the past three decades while serving as a reference source for data and concepts related to properties of surfaces and interfaces. The book opens with a brief history of the evolution of surface chemistry and reviews the nature of various surfaces and interfaces encountered in everyday life. New research in two crucial areas-nanomaterials and polymer and biopolymer interfaces-is emphasized, while important applications in tribology and catalysis, producing chemicals and fuels with high turnover and selectivity, are addressed. The basic concepts surrounding various properties of surfaces such as structure, thermodynamics, dynamics, electrical properties, and surface chemical bonds are presented. The techniques of atomic and molecular scale studies of surfaces are listed with references to up-to-date review papers. For advanced readers, this book covers recent developments in in-situ surface analysis such as high- pressure scanning tunneling microscopy, ambient pressure X-ray photoelectron spectroscopy, and sum frequency generation vibrational spectroscopy (SFG). Tables listing surface structures and data summarizing the kinetics of catalytic reactions over metal surfaces are also included. New to this edition: A discussion of new physical and chemical properties of nanoparticles Ways to utilize new surface science techniques to study properties of polymers, reaction intermediates, and mobility of atoms and molecules at surfaces Molecular-level studies on the origin of the selectivity for several catalytic reactions A microscopic understanding of mechanical properties of surfaces Updated tables of experimental data A new chapter on "soft" surfaces, polymers, and biointerfaces Introduction to Surface Chemistry and Catalysis serves as a textbook for undergraduate and graduate students taking advanced courses in physics, chemistry, engineering, and materials science, as well as researchers in surface science, catalysis science, and their applications.
Download or read book Adsorption and Its Applications in Industry and Environmental Protection Applications in environmental protection written by A. Dąbrowski and published by Elsevier Science & Technology. This book was released on 1999 with total page 1106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hardbound. Volume II contains chapters written by authoritative specialists on the broad spectrum of environmental topics in order to find a way for intense anthropogenic activities to coexist with the natural environment. The book highlights a wide spectrum of themes referring to the environmental analysis and control and molecular modelling of both sorbents and adsorption environmentally-friendly processes. Also covered are new trends in applications of colloidal science for protecting soil systems, purification and production of drinking water, water and groundwater treatment, new environmental adsorbents for removal of pollutants from wastewaters and sewages, selective sorbents for hot combustion gases, some corrosion aspects and ecological adsorption of heating and cooling pumps.The volume concludes with a comprehensive bibliography, which includes the period 1967-1997, on adsorptive separations, environmental applications, PSA, parametric pumping
Download or read book Surface structure Dependencies in Catalytic Reactions written by and published by . This book was released on 2015 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamental Concepts in Heterogeneous Catalysis written by Jens K. Nørskov and published by John Wiley & Sons. This book was released on 2014-10-27 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on a graduate course and suitable as a primer for any newcomer to the field, this book is a detailed introduction to the experimental and computational methods that are used to study how solid surfaces act as catalysts. Features include: First comprehensive description of modern theory of heterogeneous catalysis Basis for understanding and designing experiments in the field Allows reader to understand catalyst design principles Introduction to important elements of energy transformation technology Test driven at Stanford University over several semesters
Download or read book Elementary Reaction Steps in Heterogeneous Catalysis written by R.W. Joyner and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises the proceedings of a NATO sponsored Advanced Research Workshop held from 1st November to 6th November 1992 in the delightful Chateau de Florans, Bedoin, Vaucluse, France and entitled 'Elementary Reaction Steps in Heterogeneous Catalysis. ' The organisers are grateful to the Science Committee of NATO for their support of this meeting. This is believed to be the first wide ranging NATO ARW in the field of heterogeneous catalysis for 20 years, following a previous venture organised in Sardinia by Basolo and Burwell, of Northwestern University, Illinois, USA [1]. This volume collects the lecture presentations and reports on the lively Panel discussions. The idea for the meeting evolved from a series of International Symposia on Quantum Chemistry and Mechanism in Heterogeneous Catalysis. The first of these was held in Lyon, France in 1986, the second in Krakow, Poland in 1988 and the third in Berkeley, California in 1990. The organising committee of the present meeting was Bernard Bigot, France, Tony Farragher, Netherlands, Richard Joyner, UK, Mme. Danielle Olivier, France, and Rutger van Santen, Netherlands, (Chairman). We wish to thank all members of the committee but in particular Bernard Bigot, who undertook the very extensive work involved in the local organisation with consummate skill and made our stay in Provence a great pleasure. Bernard Bigot's secretary, Mme. Marie-Noelle Coscat and Richard Joyner's secretary, Mrs. Pat Gibbs, also deserve our considerable thanks. There were fifty-four participants from eleven countries.
Download or read book Quantum chemical studies of deposition and catalytic surface reactions written by Emil Kalered and published by Linköping University Electronic Press. This book was released on 2018-06-19 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum chemical calculations have been used to model chemical reactions in epitaxial growth of silicon carbide by chemical vapor deposition (CVD) processes and to study heterogeneous catalytic reactions for methanol synthesis. CVD is a common method to produce high-quality materials and e.g. thin films in the semiconductor industry, and one of the many usages of methanol is as a promising future renewable and sustainable energy carrier. To optimize the chemical processes it is essential to understand the reaction mechanisms. A comprehensive theoretical model for the process is therefore desired in order to be able to explore various variables that are difficult to investigate in situ. In this thesis reaction paths and reaction energies are computed using quantum chemical calculations. The quantum-chemical results can subsequently be used as input for thermodynamic, kinetic and computational fluid dynamics modelling in order to obtain data directly comparable with the experimental observations. For the CVD process, the effect of halogen addition to the gas mixture is studied by modelling the adsorption and diffusion of SiH2, SiCl2 and SiBr2 on the (0001?) 4H-SiC surface. SiH2 was found to bind strongest to the surface and SiBr2 binds slightly stronger than the SiCl2 molecule. The diffusion barrier is shown to be lower for SiH2 than for SiBr2 and SiCl2 which have similar barriers. SiBr2 and SiCl2 are found to have similar physisorption energies and bind stronger than the SiH2 molecule. Gibbs free-energy calculations also indicate that the SiC surface is not fully hydrogen terminated at CVD conditions since missing-neighboring pair of surface hydrogens is found to be common. Calculations for the (0001) surface show that SiCl, SiCl2, SiHCl, SiH, and SiH2 likely adsorb on a methylene site, but the processes are thermodynamically less favorable than their reverse reactions. However, the adsorbed products may be stabilized by subsequent surface reactions to form a larger structure. The formation of these larger structures is found to be fast enough to compete with the desorption processes. Also the Gibbs free energies for adsorption of Si atoms, SiX, SiX2, and SiHX where X is F or Br are presented. Adsorption of Si atoms is shown to be the most thermodynamically favorable reaction followed by SiX, SiHX, and SiX2, X being a halide. The results in this study suggest that the major Si contributors in the SiC–CVD process are Si atoms, SiX and SiH. Methanol can be synthesized from gaseous carbon dioxide and hydrogen using solid metal-metal oxide mixtures acting as heterogeneous catalysts. Since a large surface area of the catalyst enhances the speed of the heterogeneous reaction, the use of nanoparticles (NP) is expected to be advantageous due to the NPs’ large area to surface ratio. The plasma-induced creation of copper NPs is investigated. One important element during particle growth is the charging process where the variation of the work function (W) with particle size is a key quantity, and the variation becomes increasingly pronounced at smaller NP sizes. The work functions are computed for a set of NP charge numbers, sizes and shapes, using copper as a case study. A derived analytical expression for W is shown to give quite accurate estimates provided that the diameter of the NP is larger than about a nanometer and that the NP has relaxed to close to a spherical shape. For smaller sizes W deviates from the approximative expression, and also depends on the charge number. Some consequences of these results for NP charging process are outlined. Key reaction steps in the methanol synthesis reaction mechanism using a Cu/ZrO2 nanoparticle catalyst is investigated. Two different reaction paths for conversion of CO2 to CO is studied. The two paths result in the same complete reaction 2 CO2 ? 2 CO + O2 where ZrO2 (s) acts as a catalyst. The highest activation energies are significantly lower compared to that of the gas phase reaction. The presence of oxygen vacancies at the surface appear to be decisive for the catalytic process to be effective. Studies of the reaction kinetics show that when oxygen vacancies are present on the ZrO2 surface, carbon monoxide is produced within a microsecond. The IR spectra of CO2 and H2 interacting with ZrO2 and Cu under conditions that correspond to the catalyzed CH3OH production process is also studied experimentally and compared to results from the theoretical computations. Surface structures and gas-phase molecules are identified through the spectral lines by matching them to specific vibrational modes from the literature and from the new computational results. Several surface structures are verified and can be used to pin point surface structures in the reaction path. This gives important information that help decipher how the reaction mechanism of the CO2 conversion and ultimately may aid to improve the methanol synthesis process.
Download or read book Advances in Catalysis written by and published by Academic Press. This book was released on 1977-03-14 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Catalysis
Download or read book Catalyst Handbook written by Martyn V. Twigg and published by Routledge. This book was released on 2018-12-19 with total page 609 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book bridges the gap between theory and practice. It provides fundamental information on heterogeneous catalysis and the practicalities of the catalysts and processes used in producing ammonia, hydrogen and methanol via hydrocarbon steam reforming. It also covers the oxidation reactions in making formaldehyde from methanol, nitric acid from ammonia and sulphuric acid from sulphur dioxide. Designed for use in the chemical industry and by those in teaching, research and the study of industrial catalysts and catalytic processes. Students will also find this book extremely useful for obtaining practical information not available in more conventional textbooks.
Download or read book Surface Science written by Kurt W. Kolasinski and published by John Wiley & Sons. This book was released on 2002-03-29 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offers a comprehensive, modern introduction to the subject, taking a truly pedagogical approach. This text will provide the reader with a well-rounded understanding, not only of how chemistry works at surfaces, but also how to understand and probe the dynamics of surface reactions.
Download or read book Selectivity in Catalysis written by Mark E. Davis and published by . This book was released on 1993 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discusses recent research and provides tutorial chapters on enhancing selectivity in catalysis through stereoselectivity, reaction pathway control, shape selectivity, and alloys and clusters. Presents an interdisciplinary approach to increasing selectivity in homogeneous and heterogeneous catalysis research. Includes an overview chapter that discusses the current state of the field and offers a perspective on future directions.
