Download or read book Investigating the Surface Chemistry of Hydrogenation Reactions on Supported Metal Catalysts written by Megan Ingalls and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic modifiers can impact heterogeneous catalyst selectivity and activity by altering the adsorption preferences and surface reaction paths. Dually coated supported nanoparticle metal catalysts are prepared, with organic modifiers on both metal particles and their oxide support. Thiols are used to modify metals, with the sulfur head group binding to the surface, while phosphonic acids are used to modify the support. Both thiol and phosphonic acid modifiers form self-assembled monolayers (SAM) on the catalyst surface. Cinnamaldehyde hydrogenation was used to probe the performance of the as-prepared catalysts; the selectivity to cinnamyl alcohol could be potentially improved without significant decreases in activity by coating two self-assembled monolayers on the surface of the catalyst. For the dually coated catalyst, the thiol modifier mainly increased selectivity as was expected from previous work, while the phosphonate coating mainly increased the activity. When adding both thiols and phosphonates to the catalysts in different orders, it was found that the selectivity resembled the second SAM that was added to the catalyst. These changes in selectivity from the second SAM added to the surface were less drastic than the selectivity changes from a single SAM on the surface. For the activity of the catalyst, all of the catalysts with phosphonate coating showed increased activity for cinnamyl alcohol production in comparison to the uncoated Pt/Al2O3. The largest increase was seen when phosphonate was added after the thiol, likely from the thiol leaving open the selective active sites that favor cinnamyl alcohol production while the larger amount of phosphonate effected the electronic properties on the surface to increase the rate.A next potential step in this research is to use organic modifiers to tune the performance of single metal atom catalysts on oxide supports. As an initial step towards this goal, a computational model was developed to investigate hydrogenation reactions on a supported single metal atom catalyst. The catalyst modeled was a single Pt atom catalyst on the 101 surface of anatase TiO2. Acetaldehyde and trans-2-butene were used to model the functional groups in cinnamaldehyde that can be selectively hydrogenated. Multiple models were made to observe how the oxidation state of Pt0, Pt2+, and Pt4+ impacts hydrogenation reaction energies. In the Pt0 models, the adsorption of hydrogen to the surface for the reaction was unfavorable. The absence of hydrogen adsorbed to the surface would cause this catalyst to be unable to hydrogenate trans-2-butene or acetaldehyde. Both the Pt2+ and Pt4+ catalysts adsorbed hydrogen very strongly; however, this very low energy state that was created made it unfavorable for the hydrogen to leave the surface to hydrogenate the trans-2-butene and acetaldehyde.
Download or read book Supported Metals in Catalysis written by James Arthur Anderson and published by World Scientific. This book was released on 2012 with total page 581 pages. Available in PDF, EPUB and Kindle. Book excerpt: With contributions from experts in supported metal catalysis, from both the industry and academia, this book presents the latest developments in characterization and application of supported metals in heterogeneous catalysis. In addition to a thorough and updated coverage of the traditional aspects of heterogeneous catalysis such as preparation, characterization and use in well-established technologies such as Naphtha reforming, the book also includes emerging areas where supported metal catalysis will make significant contributions in future developments, such as fuel cells and fine chemicals synthesis. The second edition of Supported Metals in Catalysis comes complete with new and updated chapters containing important summaries of research in a rapidly evolving field. Very few other books deal with this highly pertinent subject matter, and as such, it is a must-have for anyone working in the field of heterogeneous catalysis.
Download or read book Surface Organometallic Chemistry Molecular Approaches to Surface Catalysis written by Jean-Marie Basset and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface organometallic chemistry is a new field bringing together researchers from organometallic, inorganic, and surface chemistry and catalysis. Topics ranging from reaction mechanisms to catalyst preparation are considered from a molecular basis, according to which the "active site" on a catalyst surface has a supra-molecular character. This. the first book on the subject, is the outcome of a NATO Workshop held in Le Rouret. France, in May. 1986. It is our hope that the following chapters and the concluding summary of recommendations for research may help to provide a definition of surface organometallic chemistry. Besides catalysis. the central theme of the Workshop, four main topics are considered: 1) Reactions of organometallics with surfaces of metal oxides, metals. and zeolites; 2) Molecular models of surfaces, metal oxides, and metals; 3) Molecular approaches to the mechanisms of surface reactions; 4) Synthesis and modification of zeolites and related microporous solids. Most surface organometallic chemistry has been carried out on amorphous high-surf ace-area metal oxides such as silica. alumina. magnesia, and titania. The first chapter. contributed by KNOZINGER. gives a short summary of the structure and reactivity of metal oxide surfaces. Most of our understanding of these surfaces is based on acid base and redox chemistry; this chemistry has developed from X-ray and spectroscopic data, and much has been inferred from the structures and reactivities of adsorbed organic probe molecules. There are major opportunities for extending this understanding by use of well-defined (single crystal) oxide surfaces and organometallic probe molecules.
Download or read book Hydrogenation written by S. David Jackson and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-09-24 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives a comprehensive overview of modern hydrogenation methods used in organic synthesis. In clearly structured chapters, the authors cover the catalysts, scope and limitations of their application, and the techniques for hydrogenation of carbon-carbon, carbon-heteroatom and heteroatom-heteroatom multiple bonds.
Download or read book Catalyst Preparation written by John Regalbuto and published by CRC Press. This book was released on 2016-04-19 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text explores the optimization of catalytic materials through traditional and novel methods of catalyst preparation, characterization, and monitoring for oxides, supported metals, zeolites, and heteropolyacids. It focuses on the synthesis of bulk materials and of heterogeneous materials, particularly at the nanoscale. The final chapters examine pretreatment, drying, finishing effects, and future applications involving catalyst preparation and the technological advances necessary for continued progress. Topics also include heat and mass transfer limitations, computation methods for predicting properties, and catalyst monitoring on laboratory and industrial scales.
Download or read book Hydrogen Effects in Catalysis written by Zoltan Paal and published by CRC Press. This book was released on 2020-09-11 with total page 777 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers hydrogen effects in catalysis in the broadest sense, from surface science to industrial applications. It draws the attention of the catalysis community to the importance of the phenomena of hydrogen effects both in the science and technology of catalysis.
Download or read book Catalysis written by James Spivey and published by Royal Society of Chemistry. This book was released on 2020-02-05 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysts are required for a variety of applications and researchers are increasingly challenged to find cost effective and environmentally benign catalysts to use. This volume looks at modern approaches to catalysis and reviews the extensive literature. Chapters highlight reactions active under oxidative coupling of methane conditions and how they are interlinked, heterogeneous nickel catalysts and their use in laboratory and industry, the reaction mechanism of heterogeneous catalysis with the surface science probe, the concepts of electroless deposition (ED) methods for preparation of true bimetallic catalysts, the general subject of metal-support interactions occurring over ruthenium-based catalysts and benzene as the target volatile organic compound (VOC). Appealing broadly to researchers in academia and industry, these illustrative chapters bridge the gap from academic studies in the laboratory to practical applications in industry not only for catalysis field but also for environmental protection. The book will be of great benefit to any researcher wanting a succinct reference on developments in this area now and looking to the future.
Download or read book Environmental Catalysis Over Gold based Materials written by George Avgouropoulos and published by Royal Society of Chemistry. This book was released on 2013 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the major developments in hydrogen-related catalytic and electrocatalytic reactions over gold-based materials over the last decade, including many of the advances made by academic and industrial researchers. Gold-based catalysts with potentially exciting new applications in hydrogen technology (e.g. purification of hydrogen, anode/cathode electrodes) are being investigated at a much higher rate than even before. A variety of techniques to synthesize, characterize and evaluate these materials is being employed. The book will be of interest to all those working in catalysis/green chemistry, in particular, to advanced level researchers in catalysis using gold-based materials. It is hoped that specialists in one reaction will read with interest the chapters on the neighbouring expertise. The book is also meant for PhD-students and advanced students interested in this area.
Download or read book New and Future Developments in Catalysis written by Hema Ramsurn and published by Elsevier Inc. Chapters. This book was released on 2013-07-13 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gold surface mediated Hydrogenation Chemistry written by Ming Pan and published by . This book was released on 2013 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: High surface area catalysts have been studied and applied in a wide range of chemical reactions and processes. The related microscopic details of surface chemistry are important and can be effectively explored employing surface science techniques. My dissertation focuses on investigations of catalytic properties of gold, primarily using vacuum molecular beam techniques, temperature programmed desorption (TPD) measurements, reflection-absorption infrared spectroscopy (RAIRS), and density functional theory (DFT) calculations. I conducted fundamental studies of hydrogenation reactions on a H atoms pre-covered Au(111) single crystal surface with co-adsorption of various chemical compounds, including acetaldehyde (CH3CHO), acetone (CH3COCH3), propionaldehyde (CH3CH2CHO), water (H2O), and nitrogen dioxide (NO2). These studies allow better understanding of hydrogenative conversions facilitated by gold catalysts, which show great promise in hydrogenation applications but for which relevant fundamental studies are lacking. The experimental results unravel the unique and remarkable catalytic activity of gold in hydrogenation reactions: i) H atoms weakly absorb on the Au(111) surface and have a low desorption activation energy of ~ 28 kJ/mol; ii) acetaldehyde can be hydrogenated to ethanol at a low temperature of
Download or read book Supported Catalysts and Their Applications written by David C Sherrington and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to improve both the efficiency and environmental acceptability of industrial processes is driving the development of heterogeneous catalysts across the chemical industry, including commodity, specialty and fine chemicals and in pharmaceuticals and agrochemicals. Drawing on international research, Supported Catalysts and their Applications discusses aspects of the design, synthesis and application of solid supported reagents and catalysts, including supported reagents for multi-step organic synthesis; selectivity in oxidation catalysis; mesoporous molecular sieve catalysts; and the use of Zeolite Beta in organic reactions. In addition, the two discrete areas of heterogeneous catalysis (inorganic oxide materials and polymer-based catalysts) that were developing in parallel are now shown to be converging, which will be of great benefit to the whole field. Providing a snapshot of the state-of-the-art in this fast-moving field, this book will be welcomed by industrialists and researchers, particularly in the agrochemicals and pharmaceuticals industries.
Download or read book New Advances in Hydrogenation Processes written by Maryam Takht Ravanchi and published by BoD – Books on Demand. This book was released on 2017-01-25 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen is one of the abundant elements on earth majorly in the form of water (H2O) and mainly as hydrogen gas (H2). Catalytic hydrogenation is a key reaction that has versatile applications in different industries. The main objective of this book is to bring together various applications of hydrogenation through the perspective of leading researchers in the field. This book is intended to be used as a graduate-level text book or as a practical guide for industrial engineers.
Download or read book Catalytic Hydrogenation written by L. Cervený and published by Elsevier. This book was released on 1986-08-01 with total page 705 pages. Available in PDF, EPUB and Kindle. Book excerpt: The collection of contributions in this volume presents the most up-to-date findings in catalytic hydrogenation. The individual chapters have been written by 36 top specialists each of whom has achieved a remarkable depth of coverage when dealing with his particular topic. In addition to detailed treatment of the most recent problems connected with catalytic hydrogenations, the book also contains a number of previously unpublished results obtained either by the authors themselves or within the organizations to which they are affiliated.Because of its topical and original character, the book provides a wealth of information which will be invaluable not only to researchers and technicians dealing with hydrogenation, but also to all those concerned with homogeneous and heterogeneous catalysis, organic technology, petrochemistry and chemical engineering.
Download or read book Advances in Catalysis written by and published by Academic Press. This book was released on 2012-12-31 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Catalysis fills the gap between the journal papers and the textbooks across the diverse areas of catalysis research. For more than 60 years Advances in Catalysis has been dedicated to recording progress in the field of catalysis and providing the scientific community with comprehensive and authoritative reviews. This series in invaluable to chemical engineers, physical chemists, biochemists, researchers and industrial chemists working in the fields of catalysis and materials chemistry. - In-depth, critical, state-of-the-art reviews - Comprehensive, covers of all aspects of catalysis research
Download or read book New Horizons in Catalysis written by T. Seiyama and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Industrial Catalysis written by Jens Hagen and published by John Wiley & Sons. This book was released on 2015-09-24 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Now in it's 3rd Edition, Industrial Catalysis offers all relevant information on catalytic processes in industry, including many recent examples. Perfectly suited for self-study, it is the ideal companion for scientists who want to get into the field or refresh existing knowledge. The updated edition covers the full range of industrial aspects, from catalyst development and testing to process examples and catalyst recycling. The book is characterized by its practical relevance, expressed by a selection of over 40 examples of catalytic processes in industry. In addition, new chapters on catalytic processes with renewable materials and polymerization catalysis have been included. Existing chapters have been carefully revised and supported by new subchapters, for example, on metathesis reactions, refinery processes, petrochemistry and new reactor concepts. "I found the book accesible, readable and interesting - both as a refresher and as an introduction to new topics - and a convenient first reference on current industrial catalytic practise and processes." Excerpt from a book review for the second edition by P. C. H. Mitchell, Applied Organometallic Chemistry (2007)
Download or read book The Catalysis of Uniform Metal Nanoparticles Deposited Onto Oxide Supports written by Nathan Musselwhite and published by . This book was released on 2015 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: Model materials consisting of metal nanoparticles loaded onto oxide supports were synthesized, characterized, and investigated in a number of catalytic chemical reactions. By varying the size, shape, and composition of nanoparticle, as well as the material used to support the nanoparticles, it was found that small changes to the catalyst can have enormous changes to the reaction activity and selectivity. Investigation of these carefully synthesized catalysts via in situ characterization, and reaction studies, leads to a deeper understanding of the molecular level parameters that govern catalysis. Through study of the properties of the nanoparticles it was discovered that nanoparticle size and shape have a dominant role in the chemoselective catalysis of furfural over platinum nanoparticles. When vapor phase furfural and hydrogen gas were passed over Pt nanoparticles ranging in size from 1.5 to 7.1 nm, the catalytic selectivity was found to be dominated by the size of the nanoparticle. Large nanoparticles promoted hydrogenation of furfural to furfuryl alcohol, while smaller nanoparticles favored decarbonylation to furan. The same size specific selectivity was found in the hydrogenative reforming (the transformation of hydrocarbons to branched isomers) of C6 hydrocarbons, in which Pt nanoparticle size controls isomerization selectivity. Methylcyclopentane was found to be extremely size dependent at lower temperatures (553 K). It was found that smaller sized nanoparticles favored isomer formation, while larger sizes catalyzed the aromatization reaction more efficiently. n-hexane was found to be much less dependent on particle size, but still showed an increase in isomerization with small particles over larger sized Pt nanoparticles. The composition of PtxRh1-x bimetallic nanoparticles was also studied. These catalysts were characterized under hexane reforming conditions with Ambient Pressure X-ray Photoelectron Spectroscopy (AP-XPS), in order to find the actual surface atomic composition under real catalytic working conditions. By using AP-XPS and catalytic data in tandem, it was found that an optimum Rh loading occurred when the surface ensemble statistically favored one Rh atom surrounded by Pt atoms. By utilizing different oxide materials for catalytic supports the flow of charge can play a role in the reaction at the surface or interface in a phenomenon known as the strong metal-support interaction (SMSI). When Pt nanoparticles were loaded onto mesoporous supports made of Co3O4, NiO, MnO2, Fe2O3, and CeO2 it was found that their activity for carbon monoxide oxidation was greatly enhanced relative to the support alone or Pt loaded onto inert mesoporous silica. This finding demonstrates that the interface of the metallic Pt nanoparticle and the oxide support is able to produce turnovers that are orders of magnitude higher than the two materials separately. When the same type of experiments were investigated with n-hexane as the reactant and macroporous Al2O3, TiO2, Nb2O5, Ta2O5, and ZrO2 were utilized as supports, it was found that the reaction selectivity was greatly altered depending on the catalytic support material. TiO2, Nb2O5, and Ta2O5 (all of which are strong Lewis acids) were found to be much more selective for isomer production than the standard SiO2 mesoporous silica supported Pt nanoparticle catalyst. Finally, an acidified mesoporous silica material was utilized as the support. This material was synthesized by using AlCl3 to modify the surface of mesoporous silica. This support was found to have no activity for hexane isomerization alone. However, when Pt nanoparticles were supported on the material, the activity and isomer selectivity in hexane reforming was increased several orders of magnitude as compared to the same nanoparticles supported on unmodified mesoporous silica. This dissertation builds on the existing knowledge of known concepts in catalysis science such as structure sensitive reactions, the metal-support interaction, and acid-base chemistry. The results show how small changes in the active sites of a catalyst can create large changes in the catalytic chemistry. This research demonstrates how careful material control, characterization and reaction study can help to elucidate the molecular level components necessary to design efficient catalysts.
