Download or read book A Density Functional Theory Study of the Oxidation of Methanol to Formaldehyde Over Vanadia Supported on Silica Titania and Zirconia written by and published by . This book was released on 2002 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: Density functional theory was used to investigate the mechanism and kinetics of methanol oxidation to formaldehyde over vanadia supported on silica, titania, and zirconia. The catalytically active site was modeled as an isolated VO4 unit attached to the support. The calculated geometry and vibrational frequencies of the active site are in good agreement with experimental measurements both for model compounds and oxide-supported vanadia. Methanol adsorption is found to occur preferentially with the rupture of a V-O-M bond (M = Si, Ti, Zr) and with preferential attachment of a methoxy group to V. The vibrational frequencies of the methoxy group are in good agreement with those observed experimentally as are the calculated isobars. The formation of formaldehyde is assumed to occur via the transfer of an H atom of a methoxy group to the O atom of the V=O group. The activation energy for this process is found to be in the range of 199-214 kJ/mol and apparent activation energies for the overall oxidation of methanol to formaldehyde are predicted to lie in the range of 112-123 kJ/mol, which is significantly higher than that found experimentally. Moreover, the predicted turnover frequency (TOF) for methanol oxidation is found to be essentially independent of support composition, whereas experiments show that the TOF is 103 greater for titania- and zirconia-supported vanadia than for silica-supported vanadia. Based on these findings, it is proposed that the formation of formaldehyde from methoxy groups may require pairs of adjacent VO4 groups or V2O-- dimer structures.
Download or read book Structure and Reactivity of Metals in Zeolite Materials written by Joaquín Pérez Pariente and published by Springer. This book was released on 2018-09-12 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides the reader with the most up-to-date and relevant knowledge on the reactivity of metals located in zeolite materials, either in framework or extra-framework positions, and the way it is connected with the nature of the chemical environment provided by the host. Since the first report of the isomorphous substitution of titanium in the framework of zeolites giving rise to materials with unusual catalytic properties, the incorporation of many other metals have been investigated with the aim for developing catalysts with improved performance in different reactions. The continuous expansion of the field, both in the variety of metals and zeolite structures, has been accompanied by an increasing focus on the relationship between the reactivity of metal centers and their unique chemical environment. The concepts covered in this volume are of interest to people working in the field of inorganic and physical chemistry, catalysis and chemical engineering, but also for those more interested in theoretical approaches to chemical reactivity. In particular the volume is useful to postgraduate students conducting research in the design, synthesis and catalytic performance of metal-containing zeolites in both academic and application contexts.
Download or read book Supported Metal Single Atom Catalysis written by Philippe Serp and published by John Wiley & Sons. This book was released on 2022-02-09 with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt: b”Supported Metal Single Atom CatalysisCovers all key aspects of supported metal single atom catalysts, an invaluable resource for academic researchers and industry professionals alike Single atom catalysis is one of the most innovative and dynamic research areas in catalysis science. Supported metal catalysts are used extensively across the chemical industry, ranging from fine and bulk chemical production to petrochemicals. Single atom catalysts (SACs) combine the advantages of both homogeneous and heterogeneous catalysts such as catalyst stability, activity, and high dispersion of the active phase. Supported Metal Single Atom Catalysis provides an authoritative and up-to-date overview of the emerging field, covering the synthesis, preparation, characterization, modeling, and applications of SACs. This comprehensive volume introduces the basic principles of single atom catalysis, describes metal oxide and carbon support materials for SAC preparation, presents characterization techniques and theoretical calculations, and discusses SACs in areas including selective hydrogenation, oxidation reactions, activation of small molecules, C-C bond formation, and biomedical applications. Highlights the activity, selectivity, and stability advantages of supported metal SACs compared to other heterogeneous catalysts Covers applications of SACs in thermal catalysis, electrocatalysis, and photocatalysis Includes chapters on single atom alloys and supported double and triple metal atom catalysts Discusses the prospects, challenges, and potential industrial applications of SACs Supported Metal Single Atom Catalysis is an indispensable reference for all those working in the fields of catalysis, solid-state chemistry, materials science, and spectroscopy, including catalytic chemists, organic chemists, electrochemists, theoretical chemists, and industrial chemists.
Download or read book Journal of the Chemical Society written by and published by . This book was released on 1991 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Density Functional Theory written by Daniel Glossman-Mitnik and published by BoD – Books on Demand. This book was released on 2019-01-30 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Density Functional Theory (or DFT for short) is a potent methodology useful for calculating and understanding the molecular and electronic structure of atoms, molecules, clusters, and solids. Its use relies not only in the ability to calculate the molecular properties of the species of interest but also provides interesting concepts that allow a better comprehension of the chemical reactivity of the studied systems. This book represents an attempt to present examples on the utility of DFT for the understanding of the chemical reactivity through descriptors that constitute the basis of the so called Conceptual DFT (sometimes also named as Chemical Reactivity Theory) as well as the application of the theory and its related computational procedures in the determination of the molecular properties of different systems of academic and industrial interest.
Download or read book Recent Developments and Applications of Modern Density Functional Theory written by Jorge M. Seminario and published by Elsevier. This book was released on 1996-11-18 with total page 863 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present status of Density Functional Theory (DFT), which has evolved as the main technique for the study of matter at the atomistic level, is described in this volume. Knowing the behavior of atoms and molecules provides a sure avenue for the design of new materials with specific features and properties in many areas of science and technology. A technique based on purely first principles allowing large savings in time and money greatly benefits the specialist or designer of new materials.The range of areas where DFT is applied has expanded and continues to do so. Any area where a molecular system is the center of attention can be studied using DFT.The scope of the 22 chapters in this book amply testifies to this.
Download or read book Density Functional Theory Study of the Selective Oxidation of Polynuclear Aromatic Hydrocarbons written by Niamh Hickey and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Density Functional Theory written by Daniel Glossman-Mitnik and published by BoD – Books on Demand. This book was released on 2022-05-18 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Density Functional Theory (DFT) is a powerful technique for calculating and comprehending the molecular and electrical structure of atoms, molecules, clusters, and solids. Its use is based not only on the capacity to calculate the molecular characteristics of the species of interest but also on the provision of interesting concepts that aid in a better understanding of the chemical reactivity of the systems under study. This book presents examples of recent advances, new perspectives, and applications of DFT for the understanding of chemical reactivity through descriptors forming the basis of Conceptual DFT as well as the application of the theory and its related computational procedures in the determination of the molecular properties of different systems of academic, social, and industrial interest.
Download or read book Advances in Density Functional Theory and Beyond for Computational Chemistry written by Wei Hu and published by Frontiers Media SA. This book was released on 2021-09-13 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Conceptual Density Functional Theory written by and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Contributions Within Density Functional Theory with Applications in Chemical Reactivity Theory and Electronegativity written by Mihai V. Putz and published by Universal-Publishers. This book was released on 2003 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the limits of the density functional theory there are introduced and deduced fundamental chemical descriptors as the chemical action concept, the chemical field, new electronegativity, rate reaction and chemical hardness formulations, the reduced total energy and the partial Hohenberg-Kohn functionals. For electronic density computations the quantum statistic picture of the path integral Feynman-Kleinert formalism is employed to its markovian approximation, providing the framework in which the majority of the chemical reactions and the reactivity of the electronic systems can be treated together with the internal and environmental couplings. Evaluation, representation and interpretation of the present analyzed chemical indices are performed for a prototype many-electronic system such that its electronic structure to display fundamental and excited anharmonic vibrations being in the thermal coupling with the medium. The chemical descriptors introduced and computed shall contribute to the foundation of the chemical reactivity on the conceptual and analytical physical bases, being able to predict the chemical transformations and the characterization of the bonds formation.
Download or read book Density Functional Theory written by David S. Sholl and published by John Wiley & Sons. This book was released on 2023-02-07 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Density Functional Theory A concise and rigorous introduction to the applications of DFT calculations In the newly revised second edition of Density Functional Theory: A Practical Introduction, the authors deliver a concise and easy-to-follow introduction to the key concepts and practical applications of density functional theory (DFT) with an emphasis on plane-wave DFT. The authors draw on decades of experience in the field, offering students from a variety of backgrounds a balanced approach between accessibility and rigor, creating a text that is highly digestible in its entirety. This new edition: Discusses in more detail the accuracy of DFT calculations and the choice of functionals Adds an overview of the wide range of available DFT codes Contains more examples on the use of DFT for high throughput materials calculations Puts more emphasis on computing phase diagrams and on open ensemble methods widely used in electrochemistry Is significantly extended to cover calculation beyond standard DFT, e.g., dispersion-corrected DFT, DFT+U, time-dependent DFT Perfect for graduate students and postdoctoral candidates in physics and engineering, Density Functional Theory: A Practical Introduction will also earn a place in the libraries of researchers and practitioners in chemistry, materials science, and mechanical engineering.
Download or read book A Density Functional Theory Study of Chemisorptions and CO Oxidation on Metal Surfaces written by Richard James Baxter and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Conceptual Density Functional Theory written by Shubin Liu and published by John Wiley & Sons. This book was released on 2022-04-13 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conceptual Density Functional Theory A unique resource that combines experimental and theoretical qualitative computing methods for a new foundation of chemical reactivity This two-volume reference book shows how conceptual density functional theory can reconcile empirical observations within silico calculations using density functional theory, molecular orbital theory, and valence bond theory. The ability to predict properties like electronegativity, acidity/basicity, strong covalent and weak intermolecular interactions as well as chemical reactivity makes DFT directly applicable to almost all problems in applied chemistry, from synthetic chemistry to catalyst design and materials characterization. Edited by one of the most recognized experts in the field and contributed to by a panel of international experts, the work addresses topics such as: Qualitative methods that are capable of rationalizing chemical concepts derived from theory and computation Fundamental concepts like the computation of chemical bonding, weak interactions, and reactivity Computational approaches for chemical concepts in excited states, extended systems, and time-dependent processes Theoretical chemists and physicists, as well as those applying theoretical calculations to empirical problems, will be able to use this book to gain unique insight into how theory intersects with experimental data in the field of qualitative computation.
Download or read book Heterogeneous Catalysis written by J. R. H. Ross and published by Elsevier. This book was released on 2011-11-07 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: Julian R.H. Ross
Download or read book Density Functional Theory Calculations written by Sergio Ricardo De Lazaro and published by BoD – Books on Demand. This book was released on 2021-02-03 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a contribution to the fast and broad Density Functional Theory (DFT) applications of the last few years. Since 2000, the DFT has grown exponentially in several computational areas because of its versatility and reliability to calculate energy from electronic density. The fast DFT’s calculations show how scientists develop more codes focused to simulate molecular and material properties reaching better conclusions than with previous theories. More powerful computers and lower computational costs have certainly assisted the increased growth of interest in this theory. Each chapter presents a specific subject contributing to a vision of the great potential of the quantum/DFT simulations in high pressure, chemical reactivity, ionic liquid, chemoinformatic, molecular docking, and non-equilibrium state.
Download or read book Recent Advances in Density Functional Methods written by Delano Pun Chong and published by World Scientific. This book was released on 1995 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last few years, much attention has been given by theoretical chemists to the development of more accurate model functionals and faster computational techniques including excited electronic states. The 8th International Conference on the Applications of Density Functional Theory to Chemistry and Physics, held in Rome, Italy, on 6-10 September 1999, gathered chemists and physicists to present and discuss state-of-the-art methodological developments and applications of density functional theory (DFT) to increasingly complex systems. The scientists shared their knowledge and experience in DFT, enabling them to face the challenges posed by the needs of high level modeling and simulation in their disciplines. The meeting was opened with an exciting lecture delivered by Nobel laureate W Kohn. The growing use of DFT in studying organic, inorganic and organometallic molecules, clusters and solids provided the basis for the success of the conference, whose main contributions are collected in this invaluable book.
