Download or read book Structure and Reactivity in Catalytic Systems Involving Metal Oxides and Electrode Surfaces written by John M. White and published by . This book was released on 1986 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Secondary ion mass spectrometry as a kinetic tool was developed was used to characterize a number of interesting metal-metal oxides and metal-adsorbate systems. The most significant of these include the behavior of rhodium and platinum on titanium dioxide thin films. We showed conclusively that the rhodium and platinum on titanium dioxide thin films. We showed conclusively that the rhodium and platinum overlayers become encapsulated with TiO when these metals on metal oxides are heated. This is the most direct evidence of longstanding interest in strong metal support interactions for the mechanism by which the interaction occurs. We have also characterized carefully the role of small amounts of impurities in noble metals and their influence on catalysis . These levels are established by secondary ion mass spectroscopy and lie below the detectability limits of Auger electron spectroscopy. Finally, we have established the kinetics of surface decomposition of species like methoxide on platinum using SIMS to monitor the decomposition channels directly.

Download or read book Metal Oxide Catalysis 2 Volume Set written by S. David Jackson and published by John Wiley & Sons. This book was released on 2008-11-24 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt: With its two-volume structure, this handbook and ready reference allows for comprehensive coverage of both characterization and applications, while uniform editing throughout ensures that the structure remains consistent. The result is an up-to-date review of metal oxides in catalysis. The first volume covers a range of techniques that are used to characterize oxides, with each chapter written by an expert in the field. Volume 2 goes on to cover the use of metal oxides in catalytic reactions. For all chemists and engineers working in the field of heterogeneous catalysis.

Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987-04 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Understanding the Catalytic Activity of Oxides Through Their Electronic Structure and Surface Chemistry written by Kelsey Ann Stoerzinger and published by . This book was released on 2016 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: The intermittent nature of renewable energy sources requires a clean, scalable means of converting and storing energy. Water electrolysis can sustainably achieve this goal by storing energy in the bonds of oxygen and hydrogen molecules. The efficiency of this storage-conversion process is largely determined by the kinetic overpotential required for the oxygen evolution and reduction reactions (OER and ORR), respectively. This thesis focuses on transition metal oxides as alternative oxygen catalysts to costly and scarce noble metals. In order to develop descriptors to improve catalytic activity, thus reducing material cost for commercial technologies, this work studies fundamental processes that occur on model catalyst systems. Electrochemical studies of epitaxial oxide thin films establish the intrinsic activity of oxide catalysts in a way that cannot be realized with polydisperse nanoparticle systems. This thesis has isolated the activity of the catalyst on a true surface-area basis, enabling an accurate comparison of catalyst chemistries, and also revealed how different terminations and structures affect the kinetics. These studies of epitaxial thin films are among the first to probe phenomena that are not straightforward to isolate in nanoparticles, such as the role of oxide band structure, interfacial charge transfer (the "ligand" effect), strain, and crystallographic orientation. In addition, these well-defined surfaces allow spectroscopic examinations of their chemical speciation in an aqueous environment by using ambient pressure X-ray photoelectron spectroscopy. By quantifying the formation of hydroxyl groups, we compare the relative affinity of different surfaces for this key reaction intermediate in oxygen electrocatalysis. The strength of interaction with hydroxyls correlates inversely with activity, illustrating detrimental effects of strong water interactions at the catalyst surface. This fundamental insight brings molecular understanding to the wetting of oxide surfaces, as well as the role of hydrogen bonding in catalysis. Furthermore, understanding of the mechanisms of oxygen electrocatalysis guides the rational design of high-surface-area oxide catalysts for technical application.

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 Metal Oxides in Heterogeneous Catalysis written by Jacques C. Vedrine and published by Elsevier. This book was released on 2018-01-11 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxides in Heterogeneous Catalysis is an overview of the past, present and future of heterogeneous catalysis using metal oxides catalysts. The book presents the historical, theoretical, and practical aspects of metal oxide-based heterogeneous catalysis. Metal Oxides in Heterogeneous Catalysis deals with fundamental information on heterogeneous catalysis, including reaction mechanisms and kinetics approaches.There is also a focus on the classification of metal oxides used as catalysts, preparation methods and touches on zeolites, mesoporous materials and Metal-organic frameworks (MOFs) in catalysis. It will touch on acid or base-type reactions, selective (partial) and total oxidation reactions, and enzymatic type reactions The book also touches heavily on the biomass applications of metal oxide catalysts and environmentally related/depollution reactions such as COVs elimination, DeNOx, and DeSOx. Finally, the book also deals with future trends and prospects in metal oxide-based heterogeneous catalysis. Presents case studies in each chapter that provide a focus on the industrial applications Includes fundamentals, key theories and practical applications of metal oxide-based heterogeneous catalysis in one comprehensive resource Edited, and contributed, by leading experts who provide perspectives on synthesis, characterization and applications

Download or read book Molecular Structure reactivity Relationships for Propane Oxidation Over Model Mixed Oxide Catalysts written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixed Mo-V-Sb-Nb and Mo-V-Te-Nb oxides were recently discovered as highly active and selective catalysts for the propane oxidation to propylene and oxygenates, i.e. acrolein and acrylic acid. Fundamental information is needed for understanding the bulk and surface molecular structure-activity/selectivity relationships and providing rules of rational design of improved mixed metal oxide catalysts for the selective oxidation of propane. The phase composition and catalytic activity of the model Mo-V-Sb-Nb-O system strongly depended on the synthesis route and composition. A number of distinct solid-state phases were observed in this system: Mo6V9O40, MoO3, rutile SbVO4 and the defect "Mo-V-Nb-O" phases. The kinetic studies indicated that the high selectivity to acrylic acid (2̃0 mol.%) was associated with the Mo6V9O40 and the defect "Mo-V-Nb-O" phases. The synthesis of these mixed Mo-V-Sb-Nb-O system was performed using combinatorial chemistry techniques to explore the utility of liquid phase automated synthesis for the reproducible preparation of these catalysts. This study indicated good reproducibility of phase compositions and catalytic properties and provided new insights into the transformation processes that occur in these oxides with time on stream. It was discovered in this research that the model mixed Mo-V-Te-O catalyst represents a simple model system for elucidating the molecular structure-activity/selectivity relationships in propane selective oxidation. This catalyst contains the two major crystalline phases proposed as active and selective for propane oxidation. This research elucidated the effect of the chemical composition, solution pH and thermal treatment on phase composition and catalytic performance. High resolution TEM study established the crystal structures of the hexagonal and orthorhombic phases in terms of their space groups, unit cell parameters, atomic coordinates and elemental compositions. In order to understand the role of the structure, morphology and composition of mixed Mo-V-Te-Nb-O system, novel synthesis approaches employing ordered arrays of colloidal polystyrene spheres (0.4 ưm) were successfully developed. These novel nanocrystalline catalysts with surface areas in the 80-110 m2/g range consisted of 20-50 nm particles of desirable catalytic phases and contained 6-20 nm pores. Kinetic studies demonstrated the acrylic acid yields exceeding 40 mol.% and approaching the commercial targets for the selective oxidation of propane to acrylic acid.

Download or read book Metal Oxides and Related Solids for Electrocatalytic Water Splitting written by Junlei Qi and published by Elsevier. This book was released on 2022-05-16 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxides and Related Solids for Electrocatalytic Water Splitting reviews the fundamentals and strategies needed to design and fabricate metal oxide-based electrocatalysts. After an introduction to the key properties of transition metal oxides, materials engineering methods to optimize the performance of metal-oxide based electrocatalysts are discussed. Strategies reviewed include defect engineering, interface engineering and doping engineering. Other sections cover important categories of metal-oxide (and related solids) based catalysts, including layered hydroxides, metal chalcogenides, metal phosphides, metal nitrides, metal borides, and more. Each chapter introduces important properties and material design strategies, including composite and morphology design. There is also an emphasis on cost-effective materials design and fabrication for optimized performance for electrocatalytic water splitting applications. Lastly, the book touches on recently developed in-situ characterization methods applied to observe and control the material synthesis process. Introduces metal oxide-based materials for electrocatalytic water splitting applications, including their key properties, synthesis, design and fabrication strategies Reviews the most relevant materials design strategies, including defect engineering, interface engineering, and doping engineering Discusses the pros and cons of metal oxide-based materials for water splitting applications to aid in materials selection

Download or read book Understanding the Role of Transition Metals and Metal Oxides on Carbon Structures for Enhancing Electrocatalytic Activity written by Angela Macedo Macedo Andrade and published by . This book was released on 2021 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The studies presented in this thesis focus on developing non-precious metal electrodes for oxygen reduction reactions (ORR), oxygen evolution reactions (OER), and hydrogen evolution reaction (HER), the core catalysis of fuel cells and electrolyzers. Metal oxides on carbon support are mainly considered as the catalytically active materials in this study. Two approaches of fabrication are presented: one based upon atomic layer deposition (ALD) and one by a wet synthesis process known as the solvothermal method. The resulting catalysts are characterized to reveal the process-performance relationship for ORR, OER, and HER. In the first study (Chapter 4), we demonstrate a bimetallic Co/Cu-embedded N-doped carbon structure for trifunctional catalysis of ORR, OER, and HER in alkaline media. A hybrid catalyst synthesized through a metal-organic framework-based process (M-NC-CoCu) enables active trifunctional catalysis due to its multi-faceted favorable characteristics. It is believed that a range of catalytically active sites are formed through the approach including well-dispersed tiny CuCo2O4 phases, a high concentration of pyridinic and graphitic N, and Cu-Ox, Cu-Nx, and Co-Nx moieties. In addition, a high-surface-area morphology with a high concentration of sp2 bonding, which is beneficial for facilitated electron conduction, further contributes to the performance as an electrocatalyst. The second study (Chapter 5) investigates the catalytic activities of titanium dioxide (TiO2) incorporated onto graphene oxygen (GO) by atomic layer deposition (ALD). The catalytic activity was systematically measured by cyclic voltammetry (CV). Evidence shows that TiO2 bonded on the surface of GO is catalytic active. An ALD treatment of TiO2 shows improvement in the catalytic activity compared to non-treated graphene. The ALD temperature also affects the catalytic performance. A higher temperature results in a higher catalytic activity, which is ascribed to the simultaneous reduction of GO and the addition of catalytically active TiO2/GO interfaces by ALD. In addition, there is also an optimal number of ALD cycles for enhanced catalytic activity. In the third study (Chapter 6), a zinc-based zeolitic imidazole framework (ZIF-8) is carbonized to form organized N-doped carbon nanostructures. The carbonized ZIF-8 (C-ZIF-8) was then used as a substrate (support) for ALD. Titanium (Ti) and/or cerium (Ce) precursors were introduced to the ALD chamber to form bimetallic (Ti and Ce) or monometallic (Ti or Ce) hybrids with C-ZIF-8. I investigated the effects of bimetal incorporation in the electrocatalytic properties of the resulting hybrid systems toward OER and HER. The optimization of ALD parameters, such as the number of cycles, temperature, and pressure for catalytic performance are also discussed.

Download or read book Springer Handbook of Surface Science written by Mario Rocca and published by Springer Nature. This book was released on 2021-01-14 with total page 1273 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook delivers an up-to-date, comprehensive and authoritative coverage of the broad field of surface science, encompassing a range of important materials such metals, semiconductors, insulators, ultrathin films and supported nanoobjects. Over 100 experts from all branches of experiment and theory review in 39 chapters all major aspects of solid-state surfaces, from basic principles to applications, including the latest, ground-breaking research results. Beginning with the fundamental background of kinetics and thermodynamics at surfaces, the handbook leads the reader through the basics of crystallographic structures and electronic properties, to the advanced topics at the forefront of current research. These include but are not limited to novel applications in nanoelectronics, nanomechanical devices, plasmonics, carbon films, catalysis, and biology. The handbook is an ideal reference guide and instructional aid for a wide range of physicists, chemists, materials scientists and engineers active throughout academic and industrial research.

Download or read book Fabrication of Metal Organic Framework Derived Nanomaterials and Their Electrochemical Applications written by Wei Xia and published by Springer. This book was released on 2018-04-03 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis systematically introduces readers to a new metal-organic framework approach to fabricating nanostructured materials for electrochemical applications. Based on the metal-organic framework (MOF) approach, it also demonstrates the latest ideas on how to create optimal MOF and MOF-derived nanomaterials for electrochemical reactions under controlled conditions. The thesis offers a valuable resource for researchers who want to understand electrochemical reactions at nanoscale and optimize materials from rational design to achieve enhanced electrochemical performance. It also serves as a useful reference guide to fundamental research on advanced electrochemical energy storage materials and the synthesis of nanostructured materials.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.

Download or read book In Situ Spectroscopy of Metal Oxides Reveal Electrocatalyst Structure property Relationships written by Chuhyon John Eom and published by . This book was released on 2020 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structure-property relationship is a foundational concept of materials science and engineering. Tuning the catalytic properties of materials by varying their structural properties like stoichiometry and crystal facets have been integral to advances in electrocatalysis. Traditionally, these studies rely on ex situ, bulk structural characterizations to describe catalytic properties. Catalysis, however, occurs on a dynamic catalytic surface sensitive to its local environment. This dissertation uses in situ spectroscopy of metal oxide electrocatalysts to better capture the intricacies of such catalyst structure-property relationships. La2/3S1/3rMnO3 films are grown using molecular beam epitaxy for a controlled study on the effects of surface and sub-surface structure of metal oxides on the oxygen reduction reaction (ORR) catalysis. Ambient pressure X-ray photoelectron spectroscopy of the films show that the surface and sub-surface structures control the balance between electronic benefits vs. parasitic surface reactions for the ORR. The low atomic number group of an amorphous cobalt oxide catalyst in a phosphate network (CoPi) is studied using home-built stimulated Raman spectroscopy (SRS). In situ SRS reveals previously unreported phosphate motifs in CoPi under oxygen evolution reaction conditions. Isotopic studies show that the phosphate structure is intimately linked to the aqueous environment with implications for the catalyst microstructure and deposition. Extensions of the dissertation on the in situ spectroscopy of a quinone electrochemical systems is discussed in the end.

Download or read book Computer Simulation of the Structure and Reactivity of Catalytic Metal Oxides written by Alan Michael Gorman and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computational Efforts Towards Efficient Catalyst Design in the Space of Oxygen Electrochemistry written by Raul Abram Flores and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid-state heterogeneous catalysts enable many of the predominant chemical reactions that drive modern society, and are critical in the chemical commodities, agriculture, and energy industries. Electrocatalysis is an important subclass of catalysis which utilizes the potential difference at electrode surfaces to drive electron transfer reactions to carry out chemical transformations. Of particular interest are the electrochemical reactions involving oxygen and water, the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) which have applications in energy technologies such as fuel cell vehicles and the electrochemical production of hydrogen, a potential alternative to fossil fuel derived hydrogen fuel. The existential crisis presented by climate change compels us to decarbonize our energy infrastructure and phase out fossil fuels. Although these green electrochemical pathways, and the catalysts that drive them, have been well studied for decades, they have yet to become economically viable to compete with fossil fuels. One promising remedy is to increase the efficiency of these processes by developing new catalyst materials, and much effort has been expended in this area. Theoretical electronic structure simulations, via density functional theory, have become indispensable tools to accelerate the design of new catalyst materials by allowing for atomistic understanding of material properties. In the first part of this thesis, we demonstrate the use DFT simulations in modeling and understanding experimental catalyst systems. First, we investigate a two-dimensional metal-organic framework consisting of various metal centers (M) and a hexaaminobenzene functional unit (HAB) known as M-HAB for the ORR. Experimental and theoretical catalytic activity results for M-HAB are presented and are shown to be consistent with one another. Additionally, we show that the DFT simulations support a linker-mediated active site instead of a metal-center active site. Next, we present experiment-theory results on the OER behavior of doped iridium-oxide thin-film catalysts and thin-film catalysts of meta-stabilized Columbite IrO2. For the doped-IrO2 catalyst system, we help elucidate the role of the dopant atom on the binding of OER intermediate species. Simulations of the columbite-IrO2 system explore the facet dependence of catalytic activity and atomistic structural factors that account for this difference. In the last couple of chapters of this work, we explore machine learning and high-throughput workflow methods to continue our investigation into iridium-oxide catalysts for the OER. First, we report an active learning based crystal structure prediction algorithm for the purpose of efficiently finding stable polymorphic phases of IrO2 and IrO3. We show that IrOx polymorphs predominately adopt octahedral coordination motifs and we demonstrate that the more oxidized IrO3 stoichiometries exhibit elevated activity over the more conventional IrO2. Lastly, we extend the polymorph discovery story by reporting on a high-throughput OER dataset composed of IrOx surface slab models created from the bulk polymorphs of the previous section. We report the theoretical OER activity of a structurally diverse set of 500 IrOx surfaces and show that the variation in OER adsorption energies can be readily modeled with structurally derived features, including a coordination based effective oxidation state descriptor which can be readily calculated for unrelaxed surfaces.

Download or read book Interplay Between Electronic Structure and Catalytic Activity in Transition Metal Oxide Model System written by Jin Suntivich and published by . This book was released on 2012 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: The efficiency of many energy storage and conversion technologies, such as hydrogen fuel cells, rechargeable metal-air batteries, and hydrogen production from water splitting, is limited by the slow kinetics of the oxygen electrochemical reactions. Transition-metal oxides can exhibit high catalytic activity for oxygen electrochemical reactions, which can be used to improve efficiency and cost of these devices. Identifying a catalyst "design principle" that links material properties to the catalytic activity can accelerate the development of highly active, abundant transition metal oxide catalysts fore more efficient, cost-effective energy storage and conversion system. In this thesis, we demonstrate that the oxygen electrocatalytic activity for perovskite transition metal oxide catalysts primarily correlates to the a* orbital ("eg") occupation. We further find that the extent of B-site transition metal-oxygen covalency can serve as a secondary activity descriptor. We hypothesize that this correlation reflects the critical influences of the a* orbital and transition metal-oxygen covalency on the ability of the surface to displace and stabilize oxygen-species on surface transition metals. We further propose that this ability to stabilize oxygen-species reflect as the rate-limiting steps of the oxygen electrochemical reactions on the perovskite oxide surfaces, and thus highlight the importance of electronic structure in controlling the oxide catalytic activity.