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Books > Science & Mathematics > Chemistry > Physical chemistry > Catalysis
This thesis describes novel strategies for the rational design of several cutting-edge high-efficiency photocatalysts, for applications such as water photooxidation, reduction, and overall splitting using a Z-Scheme system. As such, it focuses on efficient strategies for reducing energy loss by controlling charge transfer and separation, including novel faceted forms of silver phosphate for water photooxidation at record high rates, surface-basic highly polymerised graphitic carbon nitride for extremely efficient hydrogen production, and the first example of overall water splitting using a graphitic carbon nitride-based Z-Scheme system. Photocatalytic water splitting using solar irradiation can potentially offer a zero-carbon renewable energy source, yielding hydrogen and oxygen as clean products. These two ‘solar’ products can be used directly in fuel cells or combustion to provide clean electricity or other energy. Alternatively they can be utilised as separate entities for feedstock-based reactions, and are considered to be the two cornerstones of hydrogenation and oxidation reactions, including the production of methanol as a safe/portable fuel, or conventional catalytic reactions such as Fischer-Tropsch synthesis and ethylene oxide production. The main driving force behind the investigation is the fact that no photocatalyst system has yet reported combined high efficiency, high stability, and cost effectiveness; though cheap and stable, most suffer from low efficiency.
Using an in situ transmission electron microscopy (TEM) approach to investigate the growth mechanism of carbon nanotubes (CNTs) as well as the fabrication and properties of CNT-clamped metal atomic chains (MACs) is the focus of the research summarized in this thesis. The application of an in situ TEM approach in the above-mentioned research provides not only real-time observation but also monitored machining and structural evolvement at the atomic level. In this thesis, the author introduces a CNT tubular nano furnace that can be operated under TEM for investigation of the CNT nucleation mechanism. By studying the nucleation process of CNTs in the presence of various catalysts, including iron-based metallic catalysts and silicon oxide-based non-metallic catalysts, the physical states of the catalysts as well as the nucleation and growth process of CNTs are revealed. Based on the understanding of the nucleation mechanism, the author proposes a hetero-epitaxial growth strategy of CNTs from boron nitride, which provides a new route for the controllable growth of CNTs. In addition, the author presents an electron beam-assisted nanomachining technique and the fabrication of a CNT-clamped MAC prototype device based on this technique. The formation process of CNT-clamped Fe atomic chains (ACs) can be monitored with atomic resolution. The demonstrated quantized conductance and uninfluenced half-metallic properties of Fe ACs indicate that CNTs can be promising nanoscale electrodes or interconnectors for the linking and assembly of nano and subnano structures.
Troy Townsend's thesis explores the structure, energetics and activity of three inorganic nanocrystal photocatalysts. The goal of this work is to investigate the potential of metal oxide nanocrystals for application in photocatalytic water splitting, which could one day provide us with clean hydrogen fuel derived from water and solar energy. Specifically, Townsend's work addresses the effects of co-catalyst addition to niobium oxide nanotubes for photocatalytic water reduction to hydrogen, and the first use of iron oxide 'rust' in nanocrystal suspensions for oxygen production. In addition, Townsend studies a nickel/oxide-strontium titanate nanocomposite which can be described as one of only four nanoscale water splitting photocatalysts. He also examines the charge transport for this system. Overall, this collection of studies brings relevance to the design of inorganic nanomaterials for photocatalytic water splitting while introducing new directions for solar energy conversion.
This critical volume examines the different methods used for the synthesis of a great number of photocatalysts, including TiO2, ZnO and other modified semiconductors, as well as characterization techniques used for determining the optical, structural and morphological properties of the semiconducting materials. Additionally, the authors discuss photoelectrochemical methods for determining the light activity of the photocatalytic semiconductors by means of measurement of properties such as band gap energy, flat band potential and kinetics of hole and electron transfer. Photocatalytic Semiconductors: Synthesis, Characterization and Environmental Applications provide an overview of the semiconductor materials from first- to third-generation photocatalysts and their applications in wastewater treatment and water disinfection. The book further presents economic and toxicological aspects in the production and application of photocatalytic materials.
Antoine Simonneau's thesis highlights the development of new cycloisomerization reactions through the activation of alkynes with gold complexes. First Simonneau describes 1,6-enynes and their direct conversion into allenes through 1,5-hydride or ester migration processes. The author and his team used appropriate propargylic functional groups to achieve this conversion. This study shows that O-tethered 1,6-enynes carrying a strained cycloalkane at the propargylic position could undergo a cyclopropanation/ring expansion cascade reaction. The author employed this rearrangement as the starting point in the design of a new macro cycle synthesis. The next part of the thesis focuses on the cycloisomerization of diynes involving as the first step of the process the rearrangement of one alkyne partner into an allene thanks to a gold-catalyzed 1,3-shift of a propargylic ester. The thesis discloses a new cycloisomerization pattern featuring a 1,5-carbonyl transfer, giving rise to unprecedented cross-conjugated diketones. In the final part of the research, Simmoneau investigates the gold-catalyzed cycloisomerization mechanism of 1,6-enynes and questions the intermediacy of gold acetylides. By the means of NMR and mass spectrometry analysis, theoretical treatment and solution experiments, it was possible to rule out the involvement of these species in the catalytic cycle. This thesis has led to a number of publications in high-impact journals.
This book presents current research into the catalytic combustion of methane using perovskite-type oxides (ABO3). Catalytic combustion has been developed as a method of promoting efficient combustion with minimum pollutant formation as compared to conventional catalytic combustion. Recent theoretical and experimental studies have recommended that noble metals supported on (ABO3) with well-ordered porous networks show promising redox properties. Three-dimensionally ordered macroporous (3DOM) materials with interpenetrated and regular mesoporous systems have recently triggered enormous research activity due to their high surface areas, large pore volumes, uniform pore sizes, low cost, environmental benignity, and good chemical stability. These are all highly relevant in terms of the utilization of natural gas in light of recent catalytic innovations and technological advances. The book is of interest to all researchers active in utilization of natural gas with novel catalysts. The research covered comes from the most important industries and research centers in the field. The book serves not only as a text for researcher into catalytic combustion of methane, 3DOM perovskite mixed oxide, but also explores the field of green technologies by experts in academia and industry. This book will appeal to those interested in research on the environmental impact of combustion, materials and catalysis.
In this thesis, the focus is on the study of new catalytic properties of unsupported nanoporous metals in heterogeneous organic reactions under liquid-phase conditions. The author was the first to fabricate nanoporous copper with tunable nanoporosity and apply it for organic reactions. The catalyst can be reused up to ten times without loss of catalytic activity. In addition, the author developed the highly selective semihydrogenation of alkynes using nanoporous gold as a catalyst for the first time, affording Z-alkenes in 100% selectivity, which cannot be realized by traditional catalysts. All of the results described here will help readers to develop new catalytic performance of nanoporous metals for organic reactions.
This multi-authored book provides a comprehensive overview of the latest developments in porous CO2 capture materials, including ionic liquid-derived carbonaceous adsorbents, porous carbons, metal-organic frameworks, porous aromatic frameworks, micro porous organic polymers. It also reviews the sorption techniques such as cyclic uptake and desorption reactions and membrane separations. In each category, the design and fabrication, the comprehensive characterization, the evaluation of CO2 sorption/separation and the sorption/degradation mechanism are highlighted. In addition, the advantages and remaining challenges as well as future perspectives for each porous material are covered. This book is aimed at scientists and graduate students in such fields as separation, carbon, polymer, chemistry, material science and technology, who will use and appreciate this information source in their research. Other specialists may consult specific chapters to find the latest, authoritative reviews. Dr. An-Hui Lu is a Professor at the State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Faculty of Chemical, Environmental and Biological Science and Technology, Dalian University of Technology, China. Dr. Sheng Dai is a Corporate Fellow and Group Leader in the Chemical Sciences Division at Oak Ridge National Laboratory (ORNL) and a Professor of Chemistry at the University of Tennessee, USA.
The series Topics in Organometallic Chemistry presents critical overviews of research results in organometallic chemistry. As our understanding of organometallic structure, properties and mechanisms increases, new ways are opened for the design of organometallic compounds and reactions tailored to the needs of such diverse areas as organic synthesis, medical research, biology and materials science. Thus the scope of coverage includes a broad range of topics of pure and applied organometallic chemistry, where new breakthroughs are being achieved that are of significance to a larger scientific audience. The individual volumes of Topics in Organometallic Chemistry are thematic. Review articles are generally invited by the volume editors.
This book presents nine chapters based on fundamental and applied research of alternative energies. At the present time, the challenge is that technology has to come up with solutions that can provide environmentally friendly energy supply options that are able to cover the current world energy demand. Experts around the world are working on these issues for providing new solutions that will break the existing technological barriers. This book aims to address key pillars in the alternative energy field, such as: biomass energy, hydrogen energy, solar energy, wind energy, hydroelectric power, geothermal energy and their environmental implications, with the most updated progress for each pillar. It also includes the life cycle assessment (LCA) and thermoeconomic analysis (TA) as tools for evaluating and optimising environmental and cost subjects. Chapters are organized into fundamental research, applied research and future trends; and written for engineers, academic researches and scientists.
Elucidating Organic Reaction Mechanisms using photo-CIDNP Spectroscopy, by Martin Goez. Parahydrogen Induced Polarization by Homogeneous Catalysis: Theory and Applications, by Kerstin Münnemann et al. Improving NMR and MRI Sensitivity with Parahydrogen, by R. Mewis & Simon Duckett. The Solid-state Photo-CIDNP Effect, by Jörg Matysik et al. Parahydrogen-induced Polarization in Heterogeneous Catalytic Processes, by Igor Koptyug et al. Dynamic Nuclear Polarization Enhanced NMR Spectroscopy, by U. Akbey & H. Oschkinat. Photo-CIDNP NMR Spectroscopy of Amino Acids and Proteins, by Lars T. Kuhn.
The book reports on the results of the BrenaRo Winterschool 2011, held on November 21-22 in Aachen, Germany. The different chapters cover a number of aspects of the topic of energy generation, with a particular focus on energy generation from biomass. They presents new findings concerning engine development, process engineering, and biological and chemical conversion of biomass to fuels, and highlight the importance of an interdisciplinary approach, combining chemistry, biology and engineering research, to the use of renewable energy sources. All in all, this book provides readers with a snapshot of the state-of-the-art in renewable energy conversion, and gives an overview of the ongoing work in this field in Germany.
Carola Vogel's PhD thesis focuses on the synthesis, and structural and spectroscopic characterization of the first high valent iron nitride complexes. In her interdisciplinary and collaborative research Carola also describes the reactivity studies of a unique iron (V) nitride complex with water. These studies show that quantitative yields of ammonia are given at ambient conditions. High valent iron nitride and oxo species have been proposed as key intermediates in many bio-catalytic transformations, but until now these species have proven exceedingly challenging to isolate and study. Iron complexes in high oxidation states can thus serve as models for iron-containing enzymes to help us understand biological systems or aid our development of more efficient industrial catalysts.
Volume I mainly focuses on the current understanding of the reaction pathways and mechanisms involved in several important catalytic conversions of cellulose and carbohydrates. It starts with nanoscale illustrations of biomass structures and describes various reactions including cellulose depolymerization to sugars, catalytic aldose-ketose isomerization and dehydration, selective oxidation, hydrogenolysis of cellulose and sugars, and the conversion of short carbohydrates. The specificity and function of different catalysts and reaction media in relation to the catalytic performances for these reactions are discussed with significant mechanistic details. Marcel Schlaf, PhD, is a Professor at the Department of Chemistry, University of Guelph, Canada. Z. Conrad Zhang, PhD, is a Professor at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, China.
Metallic nanoparticles hold promise for their potential applications in a wide array of disciplines ranging from materials science to medicine. This book brings the power of theoretical methods to an audience of experimentalists, and explicates the simulation of metallic clusters and nanoparticles. It begins with a summary of the current state of research on metallic nanoparticles, then moves on to the current state of the art in theory of metallic nanoparticldes, and then explains why and how these tools help experimentalists. Contributions are provided by renowned experts in the field from across the world.
Palladium-Catalyzed sp2C-N Bond Forming Reactions: Recent Developments and Applications. Metal-catalyzed C(sp2)-N bond formation.- Recent Developments in Recyclable Copper Catalyst Systems for C N Bond Forming Cross-Coupling Reactions Using Aryl Halides and Arylboronic Acids. Assembly of N-containing heterocycles via Pd and Cu-catalyzed C-N bond formation reactions. Copper-Catalyzed C(aryl)-N Bond Formation.
Alistair Lennox's thesis reports on the reactivity of organotrifluoroborates, which are becoming increasingly important reagents in synthesis. The thesis is divided into three sections. The first section describes a method for preparing organotrifluoroborates. The second section reports on a mechanistic investigation into the main application of RBF3K reagents as coupling partners in Suzuki-Miyaura coupling, phenomena identified as arising from organotrifluoroborate hydrolysis and fluoride release. The final section reports on a detailed investigation into the hydrolysis mechanism, a prerequisite for their Suzuki-Miyaura coupling, and how it may be predicted and controlled. This research has uncovered many interesting and useful details and shows how problems associated with Suzuki-Miyaura coupling can best be addressed. There has already been wide industrial uptake of the new procedures and insights. The broad nature and clear and succinct style will make the thesis a valuable resource for anyone working in synthesis, organometallic chemistry, or in homogeneous catalysis.
In this thesis, Andrew Logsdail demonstrates that computational chemistry is a powerful tool in contemporary nanoscience, complementing experimental observations and helping guide future experiments. The aim of this particular PhD is to further our understanding of structural and compositional preferences in gold nanoparticles, as well as the compositional and chemical ordering preferences in bimetallic nanoalloys formed with other noble metals, such as palladium and platinum. Highlights include: calculations of the structural preferences and optical-response of gold nanoparticles and gold-containing nanoalloys; the design and implementation of novel numerical algorithms for the structural characterisation of gold nanoparticles from electron microscopy images; and electronic structure calculations investigating the interaction of gold nanoparticles with graphene and graphite substrates.The results presented here have significant implications for future research on the chemical and physical properties of gold-based nanoparticles and are of interest to many researchers working on experimental and theoretical aspects of nanoscience.
The series Topics in Current Chemistry presents critical reviews of the present and future trends in modern chemical research. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.
In the area of organic chemistry one major challenge we are currently faced with is how to assemble potentially useful molecules in new ways that generate molecular complexity and in sequences that are as efficient as possible. Our efforts in this regard, specifically for the preparation of amino containing compounds incorporating an aromatic ring, are described in this doctoral thesis. We discovered an interesting regioselectivity in an intramolecular Heck reaction, which we studied for a series of substrates that are unbiased in terms of the size of the newly formed ring, where very high levels of selectivity in relation to the new carbon-carbon bond are typically observed. DFT calculations were performed to attempt to shed light on the reaction sequence. This regioselective Heck reaction, combined with the reductive removal of the temporary amino-protecting group, allowed us to synthesize the Sceletium alkaloids: mesembrane, mesembranol and mesembrine.
Transformation and Utilization of Carbon Dioxide shows the various organic, polymeric and inorganic compounds which result from the transformation of carbon dioxide through chemical, photocatalytic, electrochemical, inorganic and biological processes. The book consists of twelve chapters demonstrating interesting examples of these reactions, depending on the types of reaction and catalyst. It also includes two chapters dealing with the utilization of carbon dioxide as a reaction promoter and presents a wide range of examples of chemistry and chemical engineering with carbon dioxide. Transformation and Utilization of Carbon Dioxide is a collective work of reviews illustrative of recent advances in the transformation and utilization of carbon dioxide. This book is interesting and useful to a wide readership in the various fields of chemical science and engineering. Bhalchandra Bhanage is a professor of industrial and engineering chemistry at Institute of Chemical Technology, India. Masahiko Arai is a professor of chemical engineering at Hokkaido University, Japan.
In this thesis, Xiaoshi Wang investigates the function and mechanism of a newly discovered heme-thiolate peroxygenase, AaeAPO. This enzyme class comes from Agrocybe aegerita and is used in the conversion of inert hydrocarbons to alcohols. Xiaoshi's work focuses on an extracellular P450 enzyme which is not limited in its stability and lack of solubility and therefore is relevant for widespread industrial use. The author demonstrates that the peroxygenase catalyzes a wide range of reactions. In some cases the author even describes very difficult transformations in molecules that are highly inert. Her detailed investigations provide a mechanistic framework for how the peroxygenase catalyzes such a large number of reactions. A major highlight of this thesis is the identification of key short-lived intermediates in the catalytic cycle of the peroxygenase, using rapid kinetic and spectroscopic methods, as well as the elucidation of the thermodynamic properties of these high-energy intermediates. This work adds new insight into an important class of enzymes.
Volume II presents the latest advances in catalytic hydrodeoxygenation and other transformations of some cellulosic platform chemicals to high value-added products. It presents the theoretical evaluation of the energetics and catalytic species involved in potential pathways of catalyzed carbohydrate conversion, pathways leading to the formation of humin-based by-products, and thermal pathways in deriving chemicals from lignin pyrolysis and hydrodeoxygenation. Catalytic gasification of biomass under extreme thermal conditions as an extension of pyrolysis is also discussed. Marcel Schlaf, PhD, is a Professor at the Department of Chemistry, University of Guelph, Canada. Z. Conrad Zhang, PhD, is a Professor at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, China.
The series Topics in Organometallic Chemistry presents critical overviews of research results in organometallic chemistry. As our understanding of organometallic structure, properties and mechanisms increases, new ways are opened for the design of organometallic compounds and reactions tailored to the needs of such diverse areas as organic synthesis, medical research, biology and materials science. Thus the scope of coverage includes a broad range of topics of pure and applied organometallic chemistry, where new breakthroughs are being achieved that are of significance to a larger scientific audience. The individual volumes of Topics in Organometallic Chemistry are thematic. Review articles are generally invited by the volume editors. All chapters from Topics in Organometallic Chemistry are published OnlineFirst with an individual DOI. In references, Topics in Organometallic Chemistry is abbreviated as Top Organomet Chem and cited as a journal
The series Topics in Organometallic Chemistry presents critical overviews of research results in organometallic chemistry. As our understanding of organometallic structure, properties and mechanisms increases, new ways are opened for the design of organometallic compounds and reactions tailored to the needs of such diverse areas as organic synthesis, medical research, biology and materials science. Thus the scope of coverage includes a broad range of topics in pure and applied organometallic chemistry, where new breakthroughs are being achieved that are of significance to a larger scientific audience. The individual volumes of Topics in Organometallic Chemistry are thematic. Review articles are generally invited by the volume editors. |
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