Download or read book Photochemical Water Oxidation by Zeolite supported Manganese Oxides written by Sweta Shrestha and published by . This book was released on 2014 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work zeolite supported manganese oxide (MnOx-Y(Cl)) clusters were studied for photochemical water oxidation. Zeolite-supported manganese oxides were synthesized by ion exchanging of cations (Mn2+ ions with or without alkaline earth metals cations) within zeolite channels and cavities followed by precipitation of manganese oxides on the surface of zeolite. Two types of catalysts were prepared: zeolite-supported manganese oxides (MnOx-Y(Cl)) and zeolite-supported alkaline earth metal cations (N) doped manganese oxides (NMnOx_Y(Cl)). Mn oxides without any support were also prepared. SEM micrographs confirmed the deposition of particles on the zeolite surface with sizes ranging from 50-80 nm. XRD diffraction patterns showed that both MnOx-Y(Cl) and NMnOx-Y(Cl) are hexagonal birnessite type (poorly ordered) layered structure MnO2. Raman scattering also showed that these manganese oxides on the zeolite surface are edge sharing MnO6 octahedra chains, as found in birnessite. XPS characterization showed that all samples had Mn valences as in birnessite. Sacrificial photochemical water oxidation using Ru(bpy)32+-persulfate system showed that zeolite supported catalysts have better catalytic performance compared to non-supported catalysts. It is proposed that the zeolite support provides better dispersion of manganese oxides on its surface, and it brings both photosensitizer and catalysts in close proximity for water oxidation. NMnOx-Y(Cl) were better catalysts than MnOx-Y(Cl) in water oxidation, and we propose that alkaline earth metals provide structural stability and integrity of the Mn oxide structure and enhances its catalytic activity. Among NMnOx-Y(Cl) catalysts, Ba2+ doped Mn oxides (BaMnOx-Y(Cl)) were the best catalysts, and is correlated with the observation that MnOx in BaMnOx-Y(Cl) possess increased surface area exposing more active sites for water oxidation. Overall, alkaline earth metals with the largest cation doped manganese oxides zeolite supported catalysts are found to be the most active water oxidizing catalyst.
Download or read book Investigation of Amorphous Manganese Oxide as a Water Oxidation Catalyst for Artificial Photosynthetic Systems written by Daniel C. Hannah and published by . This book was released on 2010 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In the context of photochemical conversion of water to hydrogen and oxygen, there is a need for catalysts which will effectively support the oxidation of water. Although ruthenium oxide and iridium oxide are well known water oxidation catalysts, it is desirable to develop catalysts based on Earth abundant metals. In nature, photosystem II relies on manganese for the oxidation of water. A study of amorphous manganese oxide as a water oxidation catalyst is reported here. Amorphous manganese oxide is found to exhibit novel behavior in this role. Oxygen evolution in aqueous suspensions of amorphous manganese oxide is observed to be the result of at least two mechanisms, at least one of which does not depend on the absorption of light. A positive correlation is observed between the average oxidation state of manganese in the material and the rate of oxygen evolution. Aqueous suspensions of amorphous manganese oxide are shown to evolve oxygen at a faster rate than previously studied catalysts within the screening system. This study demonstrates that amorphous manganese is a promising catalyst for water oxidation in artificial photosynthetic systems.
Download or read book Application of Transition Metal Coordination for Energy Efficient Processes written by Sweta Shrestha and published by . This book was released on 2017 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this dissertation is to explore the application of transition metals in two energy-intensive processes, photochemical water oxidation and olefin/paraffin separation. Photochemical water splitting is widely studied and involves the exploitation of renewable resources solar energy and water to produce clean hydrogen along with oxygen. Water oxidation process to make oxygen is not thermodynamically and kinetically feasible, thus catalysts which can promote this reaction are needed. With efficient water oxidizing catalysts, the entire water splitting process is promoted. We are focusing on birnessite as catalysts for photochemical water oxidation. Birnessite are layered manganese oxides with intercalated cations and water molecules in the interlayer space. They are known as moderate water oxidizing catalysts. We have developed two strategies to enhance water oxidizing catalytic activity of birnessite. Our first strategy was the deposition of birnessite on zeolite surfaces. The synthesis method involves ion-exchanging Mn2+ cations along with alkaline earth metal co-cations (M2+: Mg2+, Ca2+, Sr2+, Ba2+) into zeolite followed by the precipitation of manganese oxides on zeolite surfaces. M2+ cations control the loading of Mn2+ cations into zeolite, such that the larger cationic size of M2+, the lower the loading of Mn. These samples are amorphous manganese oxides and referred to as M2+MnOx-Y. After treating with high concentration of K+ cations, there was improvement in crystallinity in manganese oxides forming birnessite, and we refer to them as KMnOx-Y(M2+).
Download or read book Photochemical Conversion and Storage of Solar Energy written by John Connolly and published by Elsevier. This book was released on 2012-12-02 with total page 457 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photochemical Conversion and Storage of Solar Energy contains the proceedings of the Third International Conference on Photochemical Conversion and Storage of Solar Energy held in Boulder, Colorado, on August 3-8, 1980. The papers review the state of the art in the areas of photochemistry and photoelectrochemistry in the context of solar energy conversion and storage. Topics covered include photosynthetic quantum conversion; biomimetic systems for solar energy conversion; and photochemical electron transfer reactions in homogeneous solutions. This volume is comprised of 11 chapters and begins by describing an artificial photosynthetic system that can capture solar quanta and convert them into a stable chemical form. The discussion then turns to biomimetic approaches to solar energy conversion; fluorescent concentrators for photovoltaic cells; requirements for homogeneous photoredox chemistry in inorganic systems; and the use of inorganic components coupled with catalysts in heterogeneous assemblies for photochemical water splitting. The following chapters focus on photogalvanic cells, electrochemical photovoltaic cells, and photoelectrosynthetic reactions at the semiconductor-electrolyte interface. The final chapter examines the thermodynamic limits on photoconversion and storage of solar energy. This monograph will be of interest to chemists and other scientists concerned with the photochemical aspects of solar energy conversion and storage.
Download or read book Photochemical Charge Separation in Zeolites written by and published by . This book was released on 2001 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aluminosilicate zeolites provide an excellent host for photochemical charge separation. Because of the constraints provided by the zeolite, the back electron transfer from the reduced acceptor to the oxidized sensitizer is slowed down. This provides the opportunity to separate the charge and use it in a subsequent reaction for water oxidation and reduction. Zeolite-based ruthenium oxide catalysts have been found to be efficient for the water splitting process. This project has demonstrated the usefulness of zeolite hosts for photolytic splitting of water.
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 310 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 Electrocatalytic Water Oxidation by Manganese Oxides Ways to Influence the Catalyst Activity and Stability written by Jens Melder and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Visible Light Active Photocatalysis written by Srabanti Ghosh and published by John Wiley & Sons. This book was released on 2018-06-11 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and timely overview of this important and hot topic, with special emphasis placed on environmental applications and the potential for solar light harvesting. Following introductory chapters on environmental photocatalysis, water splitting, and applications in synthetic chemistry, further chapters focus on the synthesis and design of photocatalysts, solar energy conversion, and such environmental aspects as the removal of water pollutants, photocatalytic conversion of CO2. Besides metal oxide-based photocatalysts, the authors cover other relevant material classes including carbon-based nanomaterials and novel hybrid materials. Chapters on mechanistic aspects, computational modeling of photocatalysis and Challenges and perspectives of solar reactor design for industrial applications complete this unique survey of the subject. With its in-depth discussions ranging from a comprehensive understanding to the engineering of materials and applied devices, this is an invaluable resource for a range of disciplines.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1984 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Oxidation Catalysts written by and published by Academic Press. This book was released on 2019-06-22 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water Oxidation Catalysts, Volume 74, the latest release in the Advances in Inorganic Chemistry series, presents timely and informative summaries on current progress in a variety of subject areas. This acclaimed serial features reviews written by experts in the field, serving as an indispensable reference to advanced researchers. Users will find this to be a comprehensive overview of recent findings and trends from the last decade that covers various kinds of inorganic topics, ranging from theoretical oriented supramolecular chemistry, to the quest for accurate calculations of spin states in transition metals. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Advances in Inorganic Chemistry series Includes the latest information on water oxidation catalysts
Download or read book Catalysis for Alternative Energy Generation written by László Guczi and published by Springer Science & Business Media. This book was released on 2012-04-17 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: The increase of greenhouse gases in the atmosphere and the decrease of the available amount of fossil fuels necessitate finding new alternative and sustainable energy sources in the near future. This book summarizes the role and the possibilities of catalysis in the production of new energy carriers and in the utilization of different energy sources. The main goal of this work is to go beyond those results discussed in recent literature by identifying new developments that may lead to breakthroughs in the production of alternative energy. The book discusses the use of biomass or biomass derived materials as energy sources, hydrogen formation in methanol and ethanol reforming, biodiesel production, and the utilization of biogases. Separate sections also deal with fuel cells, photocatalysis, and solar cells, which are all promising processes for energy production that depend heavily on catalysts.
Download or read book Metal Sites in Proteins and Models written by H.A.O. Hill and published by Springer Science & Business Media. This book was released on 1999-04-01 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological chemistry is a major frontier of inorganic chemistry. Three special volumes devoted to Metal Sites in Proteins and Models address the questions: how unusual ("entatic") are metal sites in metalloproteins and metalloenzymes compared to those in small coordination complexes? and if they are special, how do polypeptide chains and co-factors control this? The chapters deal with iron, with metal centres acting as Lewis acids, metals in phosphate enzymes, with vanadium, and with the wide variety of transition metal ions which act as redox centres. They illustrate in particular how the combined armoury of genetics and structure determination at the molecular level are providing unprecedented new tools for molecular engineering.
Download or read book Advanced Oxidation Processes for Water and Wastewater Treatment written by Simon Parsons and published by IWA Publishing. This book was released on 2004-03-01 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: The suitability of Advanced Oxidation Processes (AOPs) for pollutant degradation was recognised in the early 1970s and much research and development work has been undertaken to commercialise some of these processes. AOPs have shown great potential in treating pollutants at both low and high concentrations and have found applications as diverse as ground water treatment, municipal wastewater sludge destruction and VOCs control. Advanced Oxidation Processes for Water and Wastewater Treatment is an overview of the advanced oxidation processes currently used or proposed for the remediation of water, wastewater, odours and sludge. The book contains two opening chapters which present introductions to advanced oxidation processes and a background to UV photolysis, seven chapters focusing on individual advanced oxidation processes and, finally, three chapters concentrating on selected applications of advanced oxidation processes. Advanced Oxidation Processes for Water and Wastewater Treatment will be invaluable to readers interested in water and wastewater treatment processes, including professionals and suppliers, as well as students and academics studying in this area. Dr Simon Parsons is a Senior Lecturer in Water Sciences at Cranfield University with ten years' experience of industrial and academic research and development.
Download or read book Selective Catalytic Reduction of NOx written by Oliver Kröcher and published by MDPI. This book was released on 2018-12-14 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Selective Catalytic Reduction of NOx" that was published in Catalysts
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1998 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Philippines written by Damon L. Woods and published by ABC-CLIO. This book was released on 2006 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unique, revealing look at the history and contemporary culture of the Philippine Islands and their multicultural and foreign-influenced facets. Interest in the Philippines has grown substantially over recent years. The Philippines: A Global Studies Handbook provides an all-encompassing introduction to the dramatic history of this intriguing nation as well as the contemporary social, political, economic, religious, and artistic life, written for travelers, business people, researchers, students, or general readers. The author, an award-winning professor of Asian studies, explores the effects of centuries of change and continuity on this fascinating, often contradictory land. It is a locals-eye view that gets straight to the heart of the Filipino experience—a cultural tour that measures the profound impact of the islands' Japanese, Spanish, and American conquerors, as well as the influence of Islam, the Marcos regime, and the People Power revolutions that ousted Ferdinand Marcos and, 15 years later, Joseph Estrada.
Download or read book Photochemistry written by A. Gilbert and published by Royal Society of Chemistry. This book was released on 1998 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation The breadth of scientific and technological interests in the general topic of photochemistry is truly enormous and includes, for example, such diverse areas as microelectronics, atmospheric chemistry, organic synthesis, non-conventional photoimaging, photosynthesis, solar energy conversion, polymer technologies, and spectroscopy. This Specialist Periodical Report on Photochemistry aims to provide an annual review of photo-induced processes that have relevance to the above wide-ranging academic and commercial disciplines, and interests in chemistry, physics, biology and technology. In order to provide easy access to this vast and varied literature, each volume of Photochemistry comprises sections concerned with photophysical processes in condensed phases, organic aspects which are sub-divided by chromophore type, polymer photochemistry, and photochemical aspects of solar energy conversion. Volume 34 covers literature published from July 2001 to June 2002. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading authorities in the relevant subject areas, the series creates a unique service for the active research chemist, with regular, in-depth accounts of progress in particular fields of chemistry. Subject coverage within different volumes of a given title is similar and publication is on an annual or biennial basis.
