Download or read book Ceria Supported Bimetallic Overlayer Catalysts to Aid in the Dry Reforming of Methane written by Teneil A. Schumacher and published by . This book was released on 2019 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dry reforming of methane (DRM) utilizes two abundantly available greenhouse gases, methane (CH4) and carbon dioxide (CO2), to produce industrially important syngas, hydrogen (H2) and carbon monoxide (CO), in unity. Syngas can be further treated to produce synthetic petroleum as fuels or chemicals. Most importantly, DRM serves as an important prototype reaction for sustainable chemical recycling and conversion by utilizing the major atmospheric pollutants, CH4 and CO2. It is commonly accepted that in the DRM reaction mechanism, CH4 and CO2 activate on the metal and support, respectively. Thus, the interface between the metal and the metal oxide support is also important as it provides sites to complete the reaction. Supported noble metals, such as palladium, are highly active toward the DRM reaction at high temperatures and are more resistant to carbon formation than other transition metals. However, these elements are costly for practical applications. While nickel proves to be economically favorable, deposited carbon species can accumulate on the metal which leads to loss of active sites. Furthermore, Ni is subject to sintering which also causes rapid deactivation during DRM. Previous research has shown that alloying Ni with Pd will increase catalytic activity and enhance stability against carbon formation. However, the strong Pd binding, which is required to activate CH4, also results in Pd binding too strongly to the CO and H2 products. This results in Pd surface sites being blocked and a decrease in catalytic activity. Therefore, the current global challenge for DRM is to develop thermally stable and active catalysts which can show good resistance to deactivation while minimizing use of expensive metals. Computational and experimental literature has shown that by synthesizing an overlayer of Pd on Ni (Ni@Pd), the coordination of metal atomic orbitals on the surface of a catalyst can increase. By increasing orbital coordination, the d-band center shifts down and the energy band widens. This results in a decrease of binding strength. By synthesizing a Ni@Pd overlayer, the binding strength of the overlayer metal, Pd, can be controllably decreased. By decreasing the binding strength to reactants and products, the catalyst design can then increase catalytic activity and enhance stability against carbon formation. Moreover, ceria supports provide a solution to improve the stability and catalytic performance of metal catalysts. Due to its unique redox properties, ceria may act as the active phase and remove carbon deposits on the metal by the oxidation of surface carbon to CO and prevent metal deactivation. A strong metal-support interaction between the metal and ceria can modify the structure and electronic properties of active metals which could improve the performance of metal-ceria systems. Due to ceria’s unique redox properties and oxygen storage capacities, it can better anchor the base metal as small clusters and inhibit coke formation. Furthermore, the introduction of the metal dopant, Ti, into ceria could promote its redox properties as well as enhance its thermal stability at high temperatures.
Download or read book Performance of Ceria Supported Monometallic and Bimetallic Single atom Catalysts in Carbon Monoxide Oxidation written by Nicholas A. Pantelis and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Research into atomically-dispersed metal catalysts on metal-oxide supports like ceria and alumina has grown significantly due to these catalysts' increased performance relative to bulk, nanoparticle, and sub-nanometer metal catalysts. Atomically dispersed, single atom catalysts have been shown to increase the specific activity of metal catalysts on metal-oxide supports. This study mainly focuses on difference in kinetic behavior of single-atom palladium, platinum, and nickel adatoms supported on ceria support during the oxidation of carbon monoxide. The relationship between metal weight-loading on a ceria support, reactor temperature, and reaction order was described. Bimetallic single atom catalysts of palladium and platinum on ceria were studied to compare to monometallic systems in terms of activity. Catalysts were characterized using ICP and CO-DRIFTS analysis, and a differential packed-bed reactor was used carry out the oxidation reaction; the effluent stream was analyzed using a GC to determine reaction kinetics. It was determined that CO binds most strongly to Pt, followed by Pd, and then Ni. The transition from single atom to sub-nanometer nanoparticles or nanoparticles shows a decrease in specific activity with increasing weight loading. At relatively larger weight loadings, for each metal, the order in CO transitions from above 1 to 0 (or slightly negative), while the order in O2 transitions from slightly negative or 0 to above 1. Pd, Pt, and Ni, at similar nominal weight loadings, have similar activities in different temperature ranges; this observation shows CO poisons the metal site but does not explain why at low weight loadings the order in CO increases above 1. Binding energies between metals and ceria as well as metal and CO may explain this observation. Bimetallic Pd/Pt catalysts seem to show apparent synergy due to the fact that the activation energy decreases well below the activation energy of monometallic systems of Pd and Pt.
Download or read book Heterogeneous Catalysis in Industrial Practice written by Charles N. Satterfield and published by Krieger Publishing Company. This book was released on 1996 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt: Blending theory and practice, this text provides the information needed to work with solid catalysts in the laboratory, pilot plant or commercial installation. This revised and expanded edition incorporates recent theories and industrial applications.
Download or read book Directed Synthesis and Characterization of Supported Bimetallic Overlayer Catalysts written by Michael P. Latusek and published by . This book was released on 2008 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Strong Metal support Interactions written by R. T. K. Baker and published by . This book was released on 1986 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dry Reforming of Methane on Mesoporous Ceria Based Catalysts Prepared by Hard Template Method written by Hiba Annous and published by . This book was released on 2016 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Pt and Pd Overlayer Catalysts for Aqueous Phase Reforming of Lactose and Hydrodeoygenation of Guaiacol and Anisole written by Qinghua Lai and published by . This book was released on 2016 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: Supported bimetallic overlayer catalysts, Ni@Pt, Co@Pt, Ni@Pd, and Mo@Pt have been prepared by the directed deposition synthesis technique. The single crystal and computational studies have predicted that formation of Pd or Pt overlayer on Ni, Co or Mo base metal would cause a negative shift of d-band center of surface Pd or Pt, resulting in reduced binding strength for adsorbed species. The hydrogen chemisorption, ethylene hydrogenation descriptor reaction, XRD, H2-TPR, XAS and TEM studies were employed to characterize the catalysts. The alumina supported Ni@Pt and Co@Pt overlayer catalysts have been studied for aqueous phase reforming (APR) of lactose. Silica alumina supported Ni@Pt, Ni@Pd, and Mo@Pt catalysts have been investigated for hydrodeoxygenation (HDO) of lignin derived bio-oils. The H2 chemisorption and ethylene hydrogenation descriptor showed that alumina supported Ni@Pt and Co@Pt overlayer catalysts had reduced adsorption strength compared to a Pt only catalyst, which agrees with the computational prediction. XAS results showed that overlayer catalysts exhibited higher white line intensity than Pt catalyst, indicating a negative d-band shift for the Pt overlayer. Lactose APR studies showed that lactose could be used as feedstock to produce H2 and CO under desirable reaction condition. The Pt active sites of alumina supported Ni@Pt and Co@Pt overlayer catalysts showed significantly enhanced H2 production selectivity and activity when compared with that of a Pt only catalyst. The single deposition overlayer with the largest d-band shift showed the highest H2 activity. Silica alumina supported Ni@Pd, Ni@Pt, and Mo@Pt overlayer catalysts also showed the reduced adsorption strength compared to the Pd or Pt only catalyst. The TEM images of Ni@Pd overlayer catalyst provided evidence for a core/shell type structure. The H2-TPR results demonstrated the close interaction between Pt and Mo species for Mo@Pt overlayer catalysts. Guaiacol and anisole hydrodeoxygenation results showed that Pd and Pt active sites of overlayer catalysts showed significantly enhanced deoxygenation activity compared with that of Pd or Pt only catalyst. Further studies showed that guaiacol and anisole could be completely deoxygenated over the silica alumina supported metal catalysts at high W/F, yielding benzene, toluene, and xylenes as major products.
Download or read book Classical And Quantum Dynamics In Condensed Phase Simulations Proceedings Of The International School Of Physics written by Bruce J Berne and published by World Scientific. This book was released on 1998-06-17 with total page 881 pages. Available in PDF, EPUB and Kindle. Book excerpt: The school held at Villa Marigola, Lerici, Italy, in July 1997 was very much an educational experiment aimed not just at teaching a new generation of students the latest developments in computer simulation methods and theory, but also at bringing together researchers from the condensed matter computer simulation community, the biophysical chemistry community and the quantum dynamics community to confront the shared problem: the development of methods to treat the dynamics of quantum condensed phase systems.This volume collects the lectures delivered there. Due to the focus of the school, the contributions divide along natural lines into two broad groups: (1) the most sophisticated forms of the art of computer simulation, including biased phase space sampling schemes, methods which address the multiplicity of time scales in condensed phase problems, and static equilibrium methods for treating quantum systems; (2) the contributions on quantum dynamics, including methods for mixing quantum and classical dynamics in condensed phase simulations and methods capable of treating all degrees of freedom quantum-mechanically.
Download or read book Concepts In Syngas Manufacture written by Jens Rostrup-nielsen and published by World Scientific. This book was released on 2011-07-21 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a general overview of syngas technologies as well as an in-depth analysis of the steam reforming process. Syngas is a mixture of hydrogen and carbon oxides which can be made from hydrocarbons, coal and biomass. It is an important intermediate in the chemical industry for manufacture of ammonia, methanol and other petrochemicals as well as hydrogen for refineries and fuel cells. Syngas is playing a growing role in the energy sector, because it can be converted into a number of important energy carriers and fuels. Syngas catalysis creates new options and flexibility in the complex energy network. The steam reforming process is the main technology today for manufacture of syngas. It is a complex intern-mingling of catalysis and heat transfer with restrictions caused by secondary phenomena such as carbon formation. Many of the principles are applicable for other gasification technologies of growing importance. Concepts of Syngas Preparation aims to provide a comprehensive introduction to this complex field of growing importance and gives a detailed analysis of the catalyst and process problems. This book also serves as an important link between science and industry by illustrating how the basic principles can be applied to solve design issues and operational problems./a
Download or read book The Preparation and Characterization of Highly Dispersed Supported Bimetallic Catalysts from Inorganic and Organometallic Molecular Precursors written by Bert Donald Chandler and published by . This book was released on 1999 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bimetallic Catalysts written by John H. Sinfelt and published by Wiley-Interscience. This book was released on 1983-09-29 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents an account of the research on bimetallic catalysts. Focuses attention on the possibility of influencing the selectivity of chemical transformations on metal surfaces and preparing metal alloys in a highly dispersed state. Covers the validation and elucidation of the bimetallic cluster concept. Includes figures and tables.
Download or read book Development of Novel Bimetallic Catalysts for Carbon Dioxide Reforming of Methane written by Xian Cao and published by . This book was released on 2010 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Methane Conversion written by D.M. Bibby and published by Elsevier. This book was released on 1988-03-01 with total page 759 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume comprises the invited plenary lectures, contributed and poster papers presented at a symposium organised to mark the successful inauguration of the world's first commercial plant for production of gasoline from natural gas, based on the Mobil methanol-to-gasoline process. The objectives of the Symposium were to present both fundamental research and engineering aspects of the development and commercialization of gas-to-gasoline processes. These include steam reforming, methanol synthesis and methanol-to-gasoline. Possible alternative processes e.g. MOGD, Fischer-Tropsch synthesis of hydrocarbons, and the direct conversion of methane to higher hydrocarbons were also considered.The papers in this volume provide a valuable and extremely wide-ranging overview of current research into the various options for natural gas conversion, giving a detailed description of the gas-to-gasoline process and plant. Together, they represent a unique combination of fundamental surface chemistry catalyst characterization, reaction chemistry and engineering scale-up and commercialization.
Download or read book Fuel Cells Technologies for Fuel Processing written by Dushyant Shekhawat and published by Elsevier. This book was released on 2011-03-18 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel Cells: Technologies for Fuel Processing provides an overview of the most important aspects of fuel reforming to the generally interested reader, researcher, technologist, teacher, student, or engineer. The topics covered include all aspects of fuel reforming: fundamental chemistry, different modes of reforming, catalysts, catalyst deactivation, fuel desulfurization, reaction engineering, novel reforming concepts, thermodynamics, heat and mass transfer issues, system design, and recent research and development. While no attempt is made to describe the fuel cell itself, there is sufficient description of the fuel cell to show how it affects the fuel reformer. By focusing on the fundamentals, this book aims to be a source of information now and in the future. By avoiding time-sensitive information/analysis (e.g., economics) it serves as a single source of information for scientists and engineers in fuel processing technology. The material is presented in such a way that this book will serve as a reference for graduate level courses, fuel cell developers, and fuel cell researchers. - Chapters written by experts in each area - Extensive bibliography supporting each chapter - Detailed index - Up-to-date diagrams and full colour illustrations
Download or read book Reaction Mechanisms in Carbon Dioxide Conversion written by Michele Aresta and published by Springer. This book was released on 2015-11-07 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an analysis of the reaction mechanisms relevant to a number of processes in which CO2 is converted into valuable products. Several different processes are considered that convert CO2 either in specialty chemicals or in bulk products or fuels. For each reaction, the mechanism is discussed and the assessed steps besides the dark sites of the reaction pathway are highlighted. From the insertion of CO2 into E-X bonds to the reduction of CO2 to CO or other C1 molecules or else to C2 or Cn molecules, the reactions are analysed in order to highlight the known and obscure reaction steps. Besides well known reaction mechanisms and energy profiles, several lesser known situations are discussed. Advancing knowledge of the latter would help to develop efficient routes for the conversion of CO2 into valuable products useful either in the chemical or in the energy industry. The content of this book is quite different from other books reporting the use of CO2. On account of its clear presentation, “Reaction Mechanisms in Carbon Dioxide Conversion” targets in particular researchers, teachers and PhD students.
Download or read book Natural Gas Conversion V written by A. Parmaliana and published by Elsevier. This book was released on 1998-09-17 with total page 1005 pages. Available in PDF, EPUB and Kindle. Book excerpt: On January 1988, the ascertained and economically accessible reserves of Natural Gas (NG) amounted to over 144,000 billion cubic meters worldwide, corresponding to 124 billion tons of oil equivalents (comparable with the liquid oil reserves, which are estimated to be 138 billion TOE). It is hypothesized that the volume of NG reserve will continue to grow at the same rate of the last decade. Forecasts on production indicate a potential increase from about 2,000 billion cubic meters in 1990 to not more than 3,300 billion cubic meters in 2010, even in a high economic development scenario. NG consumption represents only one half of oil: 1.9 billion TOE/y as compared to 3.5 of oil. Consequently, in the future gas will exceed oil as a carbon atom source. In the future the potential for getting energetic vectors or petrochemicals from NG will continue to grow.The topics covered in Natural Gas Conversion V reflect the large global R&D effort to look for new and economic ways of NG exploitation. These range from the direct conversion of methane and light paraffins to the indirect conversion through synthesis gas to fuels and chemicals. Particularly underlined and visible are the technologies already commercially viable.These proceedings prove that mature and technologically feasible processes for natural gas conversion are already available and that new and improved catalytic approaches are currently developing, the validity and feasibility of which will soon be documented. This is an exciting area of modern catalysis, which will certainly open novel and rewarding perspectives for the chemical, energy and petrochemical industries.
Download or read book Microwaves in Catalysis written by Satoshi Horikoshi and published by John Wiley & Sons. This book was released on 2015-12-14 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview covering the principles and preparation of catalysts, as well as reactor technology and applications in the field of organic synthesis, energy production, and environmental catalysis. Edited and authored by renowned and experienced scientists, this reference focuses on successful reaction procedures for applications in industry. Topics include catalyst preparation, the treatment of waste water and air, biomass and waste valorisation, hydrogen production, oil refining as well as organic synthesis in the presence of heterogeneous and homogeneous catalysts and continuous-flow reactions. With its practical relevance and successful methodologies, this is a valuable guide for chemists at universities working in the field of catalysis, organic synthesis, pharmaceutical or green chemistry, as well as researchers and engineers in the chemical industry.
