Download or read book Mechanistic Details for Cobalt Catalyzed Photochemical Hydrogen Production in Aqueous Solution written by and published by . This book was released on 2013 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of sunlight to drive chemical reactions that lead to the reduction of water to produce hydrogen is a potential avenue of solar energy utilization. There are many individual steps that take place in this process. This paper reports the investigation of a particular system that involves light absorbing molecules, electron donating agents and a catalyst for water reduction to hydrogen. We evaluated the efficiency of the light induced formation of a strong electron donor, the use of this donor to reduce the catalyst and finally the efficiency of the catalyst to produce hydrogen from water. From this, the sources of loss of efficiency could be clearly identified and used in the design of better systems to produce hydrogen from water.

Download or read book Mechanistic Studies of Hydrogen Evolution in Aqueous Solution Catalyzed by a Tertpyridine amine Cobalt Complex written by and published by . This book was released on 2015 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book CO2 Hydrogenation Catalysis written by Yuichiro Himeda and published by John Wiley & Sons. This book was released on 2021-06-28 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: A guide to the effective catalysts and latest advances in CO2 conversion in chemicals and fuels Carbon dioxide hydrogenation is one of the most promising and economic techniques to utilize CO2 emissions to produce value-added chemicals. With contributions from an international team of experts on the topic, CO2 Hydrogenation Catalysis offers a comprehensive review of the most recent developments in the catalytic hydrogenation of carbon dioxide to formic acid/formate, methanol, methane, and C2+ products. The book explores the electroreduction of carbon dioxide and contains an overview on hydrogen production from formic acid and methanol. With a practical review of the advances and challenges in future CO2 hydrogenation research, the book provides an important guide for researchers in academia and industry working in the field of catalysis, organometallic chemistry, green and sustainable chemistry, as well as energy conversion and storage. This important book: Offers a unique review of effective catalysts and the latest advances in CO2 conversion Explores how to utilize CO2 emissions to produce value-added chemicals and fuels such as methanol, olefins, gasoline, aromatics Includes the latest research in homogeneous and heterogeneous catalysis as well as electrocatalysis Highlights advances and challenges for future investigation Written for chemists, catalytic chemists, electrochemists, chemists in industry, and chemical engineers, CO2 Hydrogenation Catalysis offers a comprehensive resource to understanding how CO2 emissions can create value-added chemicals.

Download or read book Development of Photocatalytic Systems for Hydrogen Production from Water written by Saikat Chakraborty and published by . This book was released on 2020 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: "When produced from water in a light-driven reaction, hydrogen (H2) is a carbonfree alternative to fossil fuels. Solar H2 production draws inspiration both from nature's ability to store energy through photosynthesis and from the activity of hydrogenases. Various photocatalytic and electrocatalytic systems have been developed to reduce protons to hydrogen under different conditions. However, many of these systems frequently involve the use of noble metals and/or working in organic solvents. The research described in this thesis focuses on developing noble-metal free systems for light-driven H2 production from 100% water. These systems employed protein and peptide-derived catalysts that are water-soluble, biodegradable, free of toxic elements and amenable to future modifications. CoGGH, a Gly-Gly-His tripeptide coordinated to a cobalt ion, is shown to catalyze the reduction of aqueous protons to H2 in a light-driven reaction near neutral pH. The GGH tripeptide is a model of the ATCUN (amino-terminal copper- and nickel-binding) motif found at the N-terminus of some proteins and bioactive peptides. Using [Ru(bpy)3]2+ as a photosensitizer and ascorbic acid as an electron donor, a turnover number approaching 1000 with respect to CoGGH has been achieved, with the system remaining active for more than 48 hours. The reaction conditions that favor H2 production are consistent with a reductive quenching mechanism for producing photochemical H2. A robust, homogeneous system for light-driven hydrogen production from water is developed using a biomolecular catalyst and semiconducting nanocrystals (QDs). Acetylated cobalt microperoxidase-11 (CoMP11-Ac), a water soluble metalloporphyrin undecapeptide derived from the protein horse heart cytochrome c, can generate H2 from water at both acidic and neutral pH with [Ru(bpy)3]2+ as a photosensitizer and ascorbic acid as an electron donor. QDs are preferred to [Ru(bpy)3]2+ as a photosensitizer owing to their broad absorption spectra, higher extinction coefficient and photostability. Employing CdSe quantum dots with glutathione (GSH) capping ligands for water-solubility as photosensitizer and ascorbic acid as electron donor, H2 is produced with TONs exceeding 100, 000 with respect to CoMP11-Ac. The nature of the active catalyst and its interaction with surface capping ligands are being studied. Significant H2 production is also observed when the ligand capped QDs are used with simple metallic salts such as cobalt chloride. A photocatalytic H2 production system with GSH-capped CdSe quantum dots and a molecular cobalt catalyst yielded H2 with a TON of ~130,000 with respect to cobalt. It has been observed from elemental and electrochemical analyses that the cobalt complexes formed in-situ with capping ligands dissociated from the surface of the quantum dots are the active catalytic species in this system. Simplified ligands with some identical functional groups to GSH are being examined to provide insight into the coordination chemistry of the complexes. Finally, a new chromophore for potential applications in photocatalytic systems is developed by substitution of a cytochrome c iron with zinc (Zn-cyt c). This has a photoactive zinc protoporphyrin-IX center with low excited state reduction potential, thus making it capable of delivering electrons to a catalyst. Zn-cyt c, noncovalently bound to single-walled carbon nanotubes (SWNTs), underwent fluorescence quenching up to 95% owing to photo-induced charge transfer from the former to the latter. Deposition of Zn-cytc/SWNT films onto conductive oxide allows for harvesting of photoexcited electrons with an internal quantum efficiency of over 5%"--Pages xii-xiv

Download or read book Synthesis and Applications of Biomimetic Cobalt Thiolate Complex for Photochemical Hydrogen Production in Aqueous Phase written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Iron Porphyrins written by A. B. P. Lever and published by Wiley-VCH. This book was released on 1989-03-31 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Porphyrins play a vital role in many biological functions including oxygen transport, electron transfer and catalyzing the incorporation of oxygen into other molecules. This current survey discusses the use of modern physical techniques to probe porphyrin structure and function. The authors review the data available through a particular technique and show what can be learned therefrom about the (electronic) structure and function of biologically important porphyrins. The techniques include magnetic circular dichroism, X-ray absorption fine structure (EXAFS) and Mössbauer spectroscopies. All contributors are well known in their respective fields, enjoying world-wide reputation.

Download or read book Functional Metallosupramolecular Materials written by John George Hardy and published by Royal Society of Chemistry. This book was released on 2015-07-13 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is great interest in metallosupramolecular materials because of their use in magnetic, photonic and electronic materials. Functional Metallosupramolecular Materials focuses on the applications of these materials covering the chemistry underlying the synthesis of a variety of ligands to coordinate various metal ions and the generation of 2D and 3D materials based on these constructs. The book starts by looking at different metallosupramolecular systems including naturally occurring functional metallosupramolecular materials; DNA-based metallosupramolecular materials; metallopolymers; metallogels as well as functional materials based on MOFs. Subsequent chapters then systematically cover the different applications such as molecular computation, spin-crossover, light harvesting and as photocatalysts for the production of solar fuels. The book provides an overview of functional metallosupramolecular materials that will be of interest to graduate students, academics and industrial chemists interested in supramolecular chemistry, materials science and the materials applications.

Download or read book Non Noble Metal Catalysis written by Robertus J. M. Klein Gebbink and published by John Wiley & Sons. This book was released on 2019-04-29 with total page 610 pages. Available in PDF, EPUB and Kindle. Book excerpt: An expert overview of current research, applications, and economic and environmental advantages The study and development of new homogeneous catalysts based on first-row metals (Mn, Fe, Co, Ni, and Cu) has grown significantly due to the economic and environmental advantages that non-noble metals present. Base metals offer reduced cost, greater supply, and lower toxicity levels than noble metals?enabling greater opportunity for scientific investigation and increased development of practical applications. Non-Noble Metal Catalysis provides an authoritative survey of the field, from fundamental concepts and computational methods to industrial applications and reaction classes. Recognized experts in organometallic chemistry and homogeneous catalysis, the authors present a comprehensive overview of the conceptual and practical aspects of non-noble metal catalysts. Examination of topics including non-innocent ligands, proton-coupled electron transfer, and multi-nuclear complexes provide essential background information, while areas such as kinetic lability and lifetimes of intermediates reflect current research and shifting trends in the field. This timely book demonstrates the efficacy of base metal catalysts in the pharmaceutical, fine-chemical, and agrochemical industries, addressing both environmental and economic concerns. Providing essential conceptual and practical exploration, this valuable resource: -Illustrates how unravelling new reactivity patterns can lead to new catalysts and new applications -Highlights the multiple advantages of using non-noble metals in homogenous catalysis -Demonstrates how the availability of non-noble metal catalysis reduces costs and leads to immense savings for the chemical industry -Reveals how non-noble metal catalysis are more sustainable than noble metals such as palladium or platinum Non-Noble Metal Catalysis: Molecular Approaches and Reactions is an indispensable source of up-to-date information for catalytic chemists, organic chemists, industrial chemists, organometallic chemists, and those seeking to broaden their knowledge of catalytic chemistry.

Download or read book Photo and Electro Catalytic Processes written by Jianmin Ma and published by John Wiley & Sons. This book was released on 2022-01-25 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore green catalytic reactions with this reference from a renowned leader in the field Green reactions—like photo-, photoelectro-, and electro-catalytic reactions—offer viable technologies to solve difficult problems without significant damage to the environment. In particular, some gas-involved reactions are especially useful in the creation of liquid fuels and cost-effective products. In Photo- and Electro-Catalytic Processes: Water Splitting, N2 Fixing, CO2 Reduction, award-winning researcher Jianmin Ma delivers a comprehensive overview of photo-, electro-, and photoelectron-catalysts in a variety of processes, including O2 reduction, CO2 reduction, N2 reduction, H2 production, water oxidation, oxygen evolution, and hydrogen evolution. The book offers detailed information on the underlying mechanisms, costs, and synthetic methods of catalysts. Filled with authoritative and critical information on green catalytic processes that promise to answer many of our most pressing energy and environmental questions, this book also includes: Thorough introductions to electrocatalytic oxygen reduction and evolution reactions, as well as electrocatalytic hydrogen evolution reactions Comprehensive explorations of electrocatalytic water splitting, CO2 reduction, and N2 reduction Practical discussions of photoelectrocatalytic H2 production, water splitting, and CO2 reduction In-depth examinations of photoelectrochemical oxygen evolution and nitrogen reduction Perfect for catalytic chemists and photochemists, Photo- and Electro-Catalytic Processes: Water Splitting, N2 Fixing, CO2 Reduction also belongs in the libraries of materials scientists and inorganic chemists seeking a one-stop resource on the novel aspects of photo-, electro-, and photoelectro-catalytic reactions.

Download or read book Photochemical Water Splitting written by Neelu Chouhan and published by CRC Press. This book was released on 2017-01-27 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cleavage of water to its constituents (i.e., hydrogen and oxygen) for production of hydrogen energy at an industrial scale is one of the "holy grails" of materials science. That can be done by utilizing the renewable energy resource i.e. sunlight and photocatalytic material. The sunlight and water are abundant and free of cost available at this planet. But the development of a stable, efficient and cost-effective photocatalytic material to split water is still a great challenge. To develop the effective materials for photocatalytic water splitting, various type of materials with different sizes and structures from nano to giant have been explored that includes metal oxides, metal chalcogenides, carbides, nitrides, phosphides, and so on. Fundamental concepts and state of art materials for the water splitting are also discussed to understand the phenomenon/mechanism behind the photoelectrochemical water splitting. This book gives a comprehensive overview and description of the manufacturing of photocatalytic materials and devices for water splitting by controlling the chemical composition, particle size, morphology, orientation and aspect ratios of the materials. The real technological breakthroughs in the development of the photoactive materials with considerable efficiency, are well conversed to bring out the practical aspects of the technique and its commercialization.

Download or read book A Cobalt Complex of Bis Methylthioether Pyridine Catalyst for Hydrogen Evolution from Water written by chunli wang and published by . This book was released on 2020 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new cobalt-based catalyst, [(btep)CoBr 2 ] is produced by the reaction of CoBr 2 and bis(methylthioether)pyridine (btep), and its structure has been determined by X-ray crystallography. Our experiments suggest that this cobalt complex can used as a molecular catalyst for electrochemical and photochemical driven hydrogen evolution. As an electrocatalyst, this cobalt complex can provide 591.9 moles of hydrogen per mole of catalyst per hour (mol H 2 /mol catalyst/h) from a neutral water under an overpotential (OP) of 837.6 mV. As a co-catalyst, it was mixed with CdS nanorods (CdS NRs) as a photosensitizer, and ascorbic acid (H 2 A) as a sacrificial electron donor, and [(btep)CoBr 2 ] can provide 9326.4 mol H 2 per mole of catalyst during 40 h irradiation. The highest apparent quantum yield (AQY) is ~25.5%. The catalytic mechanism for H 2 production is investigated by several measurements and analysis.

Download or read book Springer Handbook of Inorganic Photochemistry written by Detlef Bahnemann and published by Springer Nature. This book was released on 2022-06-25 with total page 1914 pages. Available in PDF, EPUB and Kindle. Book excerpt: The handbook comprehensively covers the field of inorganic photochemistry from the fundamentals to the main applications. The first section of the book describes the historical development of inorganic photochemistry, along with the fundamentals related to this multidisciplinary scientific field. The main experimental techniques employed in state-of-art studies are described in detail in the second section followed by a third section including theoretical investigations in the field. In the next three sections, the photophysical and photochemical properties of coordination compounds, supramolecular systems and inorganic semiconductors are summarized by experts on these materials. Finally, the application of photoactive inorganic compounds in key sectors of our society is highlighted. The sections cover applications in bioimaging and sensing, drug delivery and cancer therapy, solar energy conversion to electricity and fuels, organic synthesis, environmental remediation and optoelectronics among others. The chapters provide a concise overview of the main achievements in the recent years and highlight the challenges for future research. This handbook offers a unique compilation for practitioners of inorganic photochemistry in both industry and academia.

Download or read book Metal Organic Framework Composites written by Anish Khan and published by Materials Research Forum LLC. This book was released on 2019-10-25 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of their nanoporous structures and ultra-high surface areas Metal-Organic Framework Composites (MOFs) are very interesting materials. The book focusses on the following applications: gas capture and storage, especially molecular hydrogen storage; performance enhancement of Li-ion batteries; gas separation, nano-filtration, ionic sieving, water treatment, and catalysis; sustainable renewable energy resources, electrochemical capacitors, including supercapacitors, asymmetric supercapacitors and hybrid supercapacitors; biomedical disciplines including drug delivery, theranostics; biological detection and imaging; nanoparticle photosensitizers for photodynamic therapy (PDT) and photothermal therapy (PTT). Keywords: MOF Materials, Hydrogen Storage, Renewable Energy Applications, Lithium Batteries, MOF-Quantum Dots, Clean Energy, Nanoporous MOFs, Supercapacitors, Therapeutic Applications, Biosensing, Bioimaging, Phototherapy of Cancer, Gas Separation, Nano-filtration, Ionic Sieving, Water Treatment, Drug Delivery, Theranostics; Nanoparticle Photosensitizers, Photodynamic Therapy (PDT), Photothermal Therapy (PTT).

Download or read book Cobalt Catalyzed Asymmetric Hydrogenation of Alkenes written by Hongyu Zhong and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transition metal-catalyzed hydrogenation reactions represent one of the cornerstones in homogeneous catalysis. The asymmetric hydrogenation of unsaturated molecules is an atom-economical method for the synthesis of enantio-enriched compounds and is of particular interest to the pharmaceutical, agrochemical and fine chemical industries. Catalysts based on second- and third-row transition metals, including rhodium, iridium and ruthenium, have been intensively studied in the past five decades and applied widely in industries. Thorough mechanistic studies have been carried out, facilitating catalyst designs and process optimizations. There has been a growing interest in developing relatively Earth abundant, 3d transition metal hydrogenation catalysts based on manganese, iron, cobalt and nickel as alternatives to 4d and 5d transition metals owing to their reduced cost, uninterrupted supply chains and relatively lower toxicity. First-row metals have kinetically and thermodynamically accessible oxidation states separated by one-electrons, which offers opportunities for catalyst designs with new reaction mechanisms. Despite recent progress, the understandings of catalyst speciation upon in situ activation are still limited. Elucidating the coordination chemistry, oxidation states and spin states of active catalysts is of fundamental importance to inform catalyst designs and improve the catalytic performance of first-row metals.In this dissertation, the synthesis, characterization and mechanistic studies of a host of cobalt catalysts for the asymmetric hydrogenation of carbon?carbon double bonds will be introduced. In particular, cobalt catalysts supported by chiral bidentate phosphine ligands have been identified as a ?privileged? class of catalysts and will be the focus of this dissertation.The cobalt-catalyzed asymmetric hydrogenation affording the epilepsy medication, levetiracetam, has been developed and applied to a 200-gram, pilot scale hydrogenation. The unique stability and high activity of reduced cobalt catalysts in protic solvents represent major advances for first-row alkene hydrogenation catalysts. The reaction mechanisms of enamide asymmetric hydrogenation with the formally cobalt(0) catalysts were investigated by experimental and computational methods. The enantioselectivity originates from the different reactivity of a pair of diastereomeric bis(phosphine)cobalt(0)?enamide complexes with H2. The cobalt-catalyzed asymmetric hydrogenation of ?, ?-unsaturated carboxylic acids with unusual homolytic H2 cleavage has been achieved, affording chiral acid products including Naproxen, Flurbiprofen and an L-DOPA precursor. The reactions between bis(phosphine)cobalt(II) dialkyl precatalysts and alcohols have been investigated and the bis(phosphine)Co(II) alkoxide products remained catalytically active. A cobalt-promoted methanol dehydrogenation reaction was also studied. The long-sought-after cobalt analogs of Schrock-Osborn type rhodium catalysts have been synthesized and characterized. A cationic bis(phosphine)cobalt(I) arene catalyst was discovered to be highly active for the asymmetric hydrogenation affording the type 2 diabetes medication, Sitagliptin. The ligand substitution of bis(phosphine)cobalt(0)(diene) catalysts was investigated using kinetic methods establishing a dissociative substitution mechanism. Solid state parameters and electronic structure studies imply their alternative assignment as bis(phosphine)cobalt(II) metallacyclopropane, providing a rationale for the unique protic stability. A family of cobalt precatalysts supported by the bis(phosphine), (R,R)-BenzP*, has been synthesized and characterized. The magnetic properties of dimeric bis(phosphine)Co(I)monochloride precatalysts have also been elucidated.

Download or read book Visible Light Photocatalysis in Organic Chemistry written by Corey R.J. Stephenson and published by John Wiley & Sons. This book was released on 2018-05-29 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling the need for a ready reference that reflects the vast developments in this field, this book presents everything from fundamentals, applications, various reaction types, and technical applications. Edited by rising stars in the scientific community, the text focuses solely on visible light photocatalysis in the context of organic chemistry. This primarily entails photoinduced electron transfer and energy transfer chemistry sensitized by polypyridyl complexes, yet also includes the use of organic dyes and heterogeneous catalysts. A valuable resource to the synthetic organic community, polymer and medicinal chemists, as well as industry professionals.

Download or read book Metallosurfactants written by Surinder K. Mehta and published by John Wiley & Sons. This book was released on 2022-05-31 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metallosurfactants Provides up-to-date coverage of the synthesis, properties, and applications of metallosurfactants Metallosurfactants: From Fundamentals to Catalytic and Biomedical Applications is a thorough introduction to amphiphilic compounds that allow to incorporate metal ions in the surfactant system. This comprehensive reference and guide describes the fundamentals of metal surfactant complexes, highlights recent advances in the field, and explores current and future applications and research areas. Gradually progressing from basic to advanced topics, the authors first explain the classification and characterization of metallosurfactants before delving into more complex concepts and various catalytic, sensing, and biomedical applications. The book begins with coverage of the synthesis of metallosurfactants and their surface, interfacial, and aggregation behavior. Subsequent chapters discuss applications of metallosurfactants in areas such as drug delivery, molecular machines, transfection, nanoparticle synthesis, and carbon monoxide-releasing molecules (CORMs). Other topics include the use of metallosurfactants as catalysts in organic reactions, and as anticancer and antimicrobial agents in drug delivery and formulation. This unique reference Provides an overview of the structure-function relationship, synthesis methods, and characterization of metallosurfactants Reviews current trends in metallosurfactant development and research Examines the use of metallosurfactants in a wide range of reactions, including esterolytic reactions and hydrogen generation Discusses advanced applications of metallosurfactants, e.g. as nanoreactors for nanoparticle synthesis, non-viral transfection vectors, and sensors Metallosurfactants: From Fundamentals to Catalytic and Biomedical Applications is an excellent introduction to the growing field of metallosurfactant chemistry as well as a concise, highly useful reference for researchers and scientists in both academia and industry.

Download or read book Mechanistic Understanding and Improvement of Photochemical Proton Reduction Catalyzed by Iron Carbonyl Complexes for Sustainable Hydrogen Production written by Steffen Fischer and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanistic investigation of three homogeneous, photochemical proton reduction systems that comprise Ir or Cu based photosensitizers and iron carbonyl catalysts to produce hydrogen. Operando IR spectroscopy coupled with gas volumetry was applied supported by other spectroscopic techniques. The rate determining steps, deactivation mechanisms and catalytic key species were determined, with the latter being a self-assembling [FeFe]-hydrogenase mimic in case phosphines are present as co-catalysts in the reaction mixture. These results lead to a better understanding and improvement of the systems.eng