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Synthesis Structure And Catalytic Properties Of Size Selected Platinum Nanoparticles
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Book Synopsis Synthesis, Structure, and Catalytic Properties of Size-selected Platinum Nanoparticles by : Simon Armando Mostafa Covone
Download or read book Synthesis, Structure, and Catalytic Properties of Size-selected Platinum Nanoparticles written by Simon Armando Mostafa Covone and published by . This book was released on 2010 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of heterogeneous catalysis is well established in chemical synthesis, energy, and environmental engineering applications. Supported Pt nanoparticles have been widely reported to act as catalysts in a vast number of chemical reactions. In this report, the performance of Pt/ZrO2 nanocatalyst for the decomposition of methanol, ethanol, 2-propanol, and 2-butanol is investigated. The potential of each alcohol for the production of H2 and other relevant products in the presence of a catalyst is studied. All the alcohols studied show some decomposition activity below 200°C which increased with increasing temperature. In all cases, high selectivity towards H2 formation is observed. With the exception of methanol, all alcohol conversion reactions lead to catalyst deactivation at high temperatures (T [greater than]250°C for 2-propanol and 2-butanol, T [greater than]325°C for ethanol) due to carbon poisoning. However, long-term catalyst deactivation can be avoided by optimizing reaction conditions such as operating temperature. In addition, the performance of Pt/[gamma]-Al2O3 is evaluated in the oxidation of 2-propanol. Pt nanoclusters of similar size (~1 nm diameter) but different structure (shape) were found to display distinctively different catalytic properties. All the systems studied achieve high conversion (~ 90%) below 100°C. However, flatter particles display a lower reaction onset temperature, demonstrating superior catalytic performance. Acetone, CO2, and water are generated as products indicating that both partial and complete oxidation are taking place. A number of techniques including AFM, XPS, TEM, HAADF-TEM, XAFS as well as packed-bed reactor experiments were used for sample characterization and evaluation of catalytic performance.
Download or read book Nanoalloys written by Damien Alloyeau and published by Springer Science & Business Media. This book was released on 2012-07-13 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bimetallic nanoparticles, also called nanoalloys, are at the heart of nanoscience because of their ability to tune together composition and size for specific purposes. By approaching both their physical and chemical properties, Nanoalloys: Synthesis, Structure & Properties provides a comprehensive reference to this research field in nanoscience by addressing the subject from both experimental and theoretical points of view, providing chapters across three main topics: Growth and structural properties Thermodynamics and electronic structure of nanoalloys Magnetic, optic and catalytic properties The growth and elaboration processes which are the necessary and crucial part of any experimental approach are detailed in the first chapter. Three chapters are focused on the widely used characterization techniques sensitive to both the structural arrangements and chemistry of nanoalloys. The electronic structure of nanoalloys is described as a guide of useful concepts and theoretical tools. Chapters covering thermodynamics begin with bulk alloys, going to nanoalloys via surfaces in order to describe chemical order/disorder, segregation and phase transitions in reduced dimension. Finally, the optical, magnetic and catalytic properties are discussed by focusing on nanoparticles formed with one element to track the modifications which occur when forming nanoalloys. The range and detail of Nanoalloys: Synthesis, Structure & Properties makes it an ideal resource for postgraduates and researchers working in the field of nanoscience looking to expand and support their knowledge of nanoalloys.
Book Synopsis The Synthesis, Characterization and Catalytic Reaction Studies OfMonodisperse Platinum Nanoparticles in Mesoporous Oxide Materials by : Robert M. Rioux
Download or read book The Synthesis, Characterization and Catalytic Reaction Studies OfMonodisperse Platinum Nanoparticles in Mesoporous Oxide Materials written by Robert M. Rioux and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Controlled Synthesis of Pt-Ni Bimetallic Catalysts and Study of Their Catalytic Properties by : Yuen Wu
Download or read book Controlled Synthesis of Pt-Ni Bimetallic Catalysts and Study of Their Catalytic Properties written by Yuen Wu and published by Springer. This book was released on 2016-05-14 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the controlled synthesis of Pt–Ni bimetallic nanoparticles and the study of their catalytic properties. It discusses in detail the nucleation mechanism and the growth process of bimetallic systems, which is vital for a deeper understanding of the design of bimetallic catalysts. The author presents four pioneering studies: (1) syntheses of water-soluble octahedral, truncated octahedral, and cubic Pt–Ni nanocrystals and the study of their structure-activity relationship in model hydrogenation reactions; (2) a strategy for designing a concave Pt–Ni alloy using controllable chemical etching; (3) defect-dominated shape recovery of nanocrystals, which is a new synthesis strategy for trimetallic catalysts; (4) a sophisticated construction of Au islands on Pt−Ni, which is an ideal trimetallic nanoframe catalyst. This thesis inspires researchers working in materials, catalysis as well as other interdisciplinary areas.
Book Synopsis Metal Nanoclusters in Catalysis and Materials Science: The Issue of Size Control by : Benedetto Corain
Download or read book Metal Nanoclusters in Catalysis and Materials Science: The Issue of Size Control written by Benedetto Corain and published by Elsevier. This book was released on 2011-08-11 with total page 471 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Nanoclusters in Catalysis and Materials Science: The Issue of Size Control deals with the synthesis of metal nanoclusters along all known methodologies. Physical and chemical properties of metal nanoclusters relevant to their applications in chemical processing and materials science are covered thoroughly. Special attention is given to the role of metal nanoclusters size and shape in catalytic processes and catalytic applications relevant to industrial chemical processing.An excellent text for expanding the knowledge on the chemistry and physics of metal nanoclusters. Divided in two parts; Part I deals with general aspects of the matter and Part II has to be considered a useful handbook dealing with the production of metal nanoclusters, especially from their size-control point of view. * Divided into two parts for ease of reference: general and operational * Separation of synthetic aspects, physical properties and applications* Specific attention is given to the task of metal nanoclusters size-control
Book Synopsis Synthesis, Structure and Catalytic Activity of Some Platinum Group Metal Complexes by : Tallit Ghaffar
Download or read book Synthesis, Structure and Catalytic Activity of Some Platinum Group Metal Complexes written by Tallit Ghaffar and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Metal Nanoparticles for Catalysis by : Franklin Tao
Download or read book Metal Nanoparticles for Catalysis written by Franklin Tao and published by Royal Society of Chemistry. This book was released on 2014-06-12 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysis is a central topic in chemical transformation and energy conversion. Thanks to the spectacular achievements of colloidal chemistry and the synthesis of nanomaterials over the last two decades, there have also been significant advances in nanoparticle catalysis. Catalysis on different metal nanostructures with well-defined structures and composition has been extensively studied. Metal nanocrystals synthesized with colloidal chemistry exhibit different catalytic performances in contrast to metal nanoparticles prepared with impregnation or deposition precipitation. Additionally, theoretical approaches in predicting catalysis performance and understanding catalytic mechanism on these metal nanocatalysts have made significant progress. Metal Nanoparticles for Catalysis is a comprehensive text on catalysis on Nanoparticles, looking at both their synthesis and applications. Chapter topics include nanoreactor catalysis; Pd nanoparticles in C-C coupling reactions; metal salt-based gold nanocatalysts; theoretical insights into metal nanocatalysts; and nanoparticle mediated clock reaction. This book bridges the gap between nanomaterials synthesis and characterization, and catalysis. As such, this text will be a valuable resource for postgraduate students and researchers in these exciting fields.
Book Synopsis Synthesis of Platinum Based Nanocatalysts with Controlled Particle Parameters and Study for Their Properties in Oxidation Reactions by : Sang Youp Hwang
Download or read book Synthesis of Platinum Based Nanocatalysts with Controlled Particle Parameters and Study for Their Properties in Oxidation Reactions written by Sang Youp Hwang and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Controllable nanoparticles with different morphology, alloy, composition, and sizes were investigated and analyzed. The nanoparticles, which act as a catalyst, are synthesized using solid state and wet chemistry method. The synthesized catalysts also were demonstrated for the various chemical reactions, such as CO oxidation and CO preferential oxidation (PROX). Group VIII metal nanoparticles with variant morphologies are synthesized under carbon monoxide atmosphere. The important roles of CO in determining the surface formation of growing particles are studied by both experiments and density functional theory calculations, which suggest different growth mechanisms for these metals. Alumina-supported platinum-silver alloy nanoparticle (Pt-Ag/Al2O3) catalysts have been prepared using a wet chemistry method and studied for the property in carbon monoxide oxidation reaction. The Pt-Ag alloy catalyst exhibits significantly improved activity and largely decreased activation energy barrier comparing to both pure Pt and pure Ag catalysts in the room temperature range. The Langmuir-Hinshelwood mechanism, in which surface Pt active sites chemisorb CO and adjacent Ag sites activate O2, was proposed and discussed for explaining the promoted CO oxidation kinetics on the Pt-Ag alloy. Octahedral Pt3Ni alloy nanoparticles on carbon and alumina supports are prepared and tested for CO preferential oxidation (PROX) in H2. Both catalysts exhibit much superior PROX property with high activity and 100% selectivity between around RT and 100 °C. The improved activity of the octahedral Pt3Ni has been attributed to bifunctional sites mechanism. The excellent selectivity is correlated with the unique surface geometry and electronic structure of the octahedral Pt3Ni. Pt/SiO2 catalysts with different Pt nanoparticle size are prepared using an impregnation method. The 2.4 nm Pt/SiO2 exhibits improved CO oxidation activity and turnover frequency (TOF) comparing to either bigger or smaller Pt catalysts. The different catalytic activities are related with the adsorption energy, which is caused by the different electronic structure such as d-band center and work function. Cubic and spherical PtMn alloy nanoparticles on alumina were synthesized and tested for CO preferential oxidation (PROX). Both catalysts exhibited 100% CO selectivity in a wide temperature window. The extended temperature windows for CO PROX on PtMn have been attributed to a low reducibility of Mn oxide. The findings of high selectivity in a broad temperature window were confirmed using various Pt alloy catalysts with a different reducibility of surface oxide.
Book Synopsis PEM Fuel Cell Electrocatalysts and Catalyst Layers by : Jiujun Zhang
Download or read book PEM Fuel Cell Electrocatalysts and Catalyst Layers written by Jiujun Zhang and published by Springer Science & Business Media. This book was released on 2008-08-26 with total page 1147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane (PEM) fuel cells are promising clean energy converting devices with high efficiency and low to zero emissions. Such power sources can be used in transportation, stationary, portable and micro power applications. The key components of these fuel cells are catalysts and catalyst layers. “PEM Fuel Cell Electrocatalysts and Catalyst Layers” provides a comprehensive, in-depth survey of the field, presented by internationally renowned fuel cell scientists. The opening chapters introduce the fundamentals of electrochemical theory and fuel cell catalysis. Later chapters investigate the synthesis, characterization, and activity validation of PEM fuel cell catalysts. Further chapters describe in detail the integration of the electrocatalyst/catalyst layers into the fuel cell, and their performance validation. Researchers and engineers in the fuel cell industry will find this book a valuable resource, as will students of electrochemical engineering and catalyst synthesis.
Book Synopsis Controlling the Growth and Catalytic Activity of Platinum Nanoparticles Using Peptide and Polymer Ligands by : Lauren Marie Forbes
Download or read book Controlling the Growth and Catalytic Activity of Platinum Nanoparticles Using Peptide and Polymer Ligands written by Lauren Marie Forbes and published by . This book was released on 2013 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heterogeneous catalysts have widespread industrial applications. Platinum nanomaterials in particular, due to their particularly high electrocatalytic activity and durability, are used to catalyze a wide variety of reactions, including oxygen reduction, which is frequently used as the cathode reaction in fuel cells. As platinum is a very expensive material, a high priority in fuel cell research is the exploration of less expensive, more efficient catalysts for the oxygen reduction reaction (ORR). We demonstrate here the use of phage display to identify peptides that bind to Pt (100) which were then used to synthesize platinum cubes in solution. However, while the peptides were able to control particle growth, the bio-synthesized Pt particles showed extremely poor activity when tested for ORR. This could be attributed to peptide coverage on the surface or strong interactions between particular amino acids and the metal that are detrimental for catalysis. To investigate this further, we decided to investigate the role of individual amino acids on Pt nanocrystal synthesis and catalysis. For this, we conjugated the R-groups of single amino acids to polyethylene glycol (PEG) chains. Through this work we have determined that the identity of the amino acid R-group is important in both the synthesis and the catalytic activity of the particles. For Pt nanoparticle synthesis, we found that the hydrophobicity of the functional groups affected their ability to interact well with the particles during nucleation and growth, and thus only the hydrophilic functional groups were capable of mediating the synthesis to produce well-defined faceted particles. With respect to ORR, we found distinct trends that showed that the inclusion of certain amino acids could significantly enhance catalysis- even at high polymer loadings. This work presents evidence that counters the common conception that organic capping ligands decrease catalytic activity; in fact activity may actually be improved over bare metal through judicious choice and design of ligands that inhibit Pt oxidation and control chain packing at the Pt surface. Therefore, it may be possible to have ligands on a nanoparticle surface that allow the particles to be well-dispersed on an electrode surface, while simultaneously enhancing catalysis.
Book Synopsis Green Synthesis, Characterization and Applications of Nanoparticles by : Ashutosh Kumar Shukla
Download or read book Green Synthesis, Characterization and Applications of Nanoparticles written by Ashutosh Kumar Shukla and published by Elsevier. This book was released on 2018-11-26 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: Green Synthesis, Characterization and Applications of Nanoparticles shows how eco-friendly nanoparticles are engineered and used. In particular, metal nanoparticles, metal oxide nanoparticles and other categories of nanoparticles are discussed. The book outlines a range of methodologies and explores the appropriate use of each. Characterization methods include spectroscopic, microscopic and diffraction methods, but magnetic resonance methods are also included as they can be used to understand the mechanism of nanoparticle synthesis using organisms. Applications covered include targeted drug delivery, water purification and hydrogen generation. This is an important research resource for those wishing to learn more about how eco-efficient nanoparticles can best be used. Theoretical details and mathematical derivations are kept to a necessary minimum to suit the need of interdisciplinary audiences and those who may be relatively new to the field. Explores recent trends in growth, characterization, properties and applications of nanoparticles Gives readers an understanding on how they are applied through the use of case studies and examples Assesses the advantages and disadvantages of a variety of synthesis and characterization techniques for green nanoparticles in different situations
Book Synopsis Advanced Nanomaterials for Catalysis and Energy by : Vladislav A. Sadykov
Download or read book Advanced Nanomaterials for Catalysis and Energy written by Vladislav A. Sadykov and published by Elsevier. This book was released on 2018-08-27 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced Nanomaterials for Catalysis and Energy: Synthesis, Characterization and Applications outlines new approaches to the synthesis of nanomaterials (synthesis in flow conditions, laser electrodispersion of single metals or alloys on carbon or oxide supports, mechanochemistry, sol-gel routes, etc.) to provide systems with a narrow particle size distribution, controlled metal-support interaction and nanocomposites with uniform spatial distribution of domains of different phases, even in dense sintered materials. Methods for characterization of real structure and surface properties of nanomaterials are discussed, including synchrotron radiation diffraction and X-ray photoelectron spectroscopy studies, neutronography, transmission/scanning electron microscopy with elemental analysis, and more. The book covers the effect of nanosystems' composition, bulk and surface properties, metal-support interaction, particle size and morphology, deposition density, etc. on their functional properties (transport features, catalytic activity and reaction mechanism). Finally, it includes examples of various developed nanostructured solid electrolytes and mixed ionic-electronic conductors as materials in solid oxide fuel cells and asymmetric supported membranes for oxygen and hydrogen separation. Outlines synthetic and characterization methods for nanocatalysts Relates nanocatalysts' properties to their specific applications Proposes optimization methods aiming at specific applications
Book Synopsis Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts by :
Download or read book Monodisperse Platinum and Rhodium Nanoparticles as Model Heterogeneous Catalysts written by and published by . This book was released on 2008 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Model heterogeneous catalysts have been synthesized and studied to better understand how the surface structure of noble metal nanoparticles affects catalytic performance. In this project, monodisperse rhodium and platinum nanoparticles of controlled size and shape have been synthesized by solution phase polyol reduction, stabilized by polyvinylpyrrolidone (PVP). Model catalysts have been developed using these nanoparticles by two methods: synthesis of mesoporous silica (SBA-15) in the presence of nanoparticles (nanoparticle encapsulation, NE) to form a composite of metal nanoparticles supported on SBA-15 and by deposition of the particles onto a silicon wafer using Langmuir-Blodgett (LB) monolayer deposition. The particle shapes were analyzed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM) and the sizes were determined by TEM, X-ray diffraction (XRD), and in the case of NE samples, room temperature H2 and CO adsorption isotherms. Catalytic studies were carried out in homebuilt gas-phase reactors. For the nanoparticles supported on SBA-15, the catalysts are in powder form and were studied using the homebuilt systems as plug-flow reactors. In the case of nanoparticles deposited on silicon wafers, the same systems were operated as batch reactors. This dissertation has focused on the synthesis, characterization, and reaction studies of model noble metal heterogeneous catalysts. Careful control of particle size and shape has been accomplished though solution phase synthesis of Pt and Rh nanoparticles in order to elucidate further structure-reactivity relationships in noble metal catalysis.
Book Synopsis Nanoparticle Design and Characterization for Catalytic Applications in Sustainable Chemistry by : Rafael Luque
Download or read book Nanoparticle Design and Characterization for Catalytic Applications in Sustainable Chemistry written by Rafael Luque and published by Royal Society of Chemistry. This book was released on 2019-10-05 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an introduction to the preparation and characterisation of nanomaterials and their design for specific catalytic applications.
Book Synopsis Kinetics of Heterogeneous Catalytic Reactions by : Michel Boudart
Download or read book Kinetics of Heterogeneous Catalytic Reactions written by Michel Boudart and published by Princeton University Press. This book was released on 2014-07-14 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a critical account of the principles of the kinetics of heterogeneous catalytic reactions in the light of recent developments in surface science and catalysis science. Originally published in 1984. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.
Book Synopsis The Catalysis of Uniform Metal Nanoparticles Deposited Onto Oxide Supports by : Nathan Musselwhite
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.
Download or read book פדולוגיה ופיסיקה של הקרקע written by and published by . This book was released on 1966 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
