Download or read book Novel Magnetically Recyclable MoS2 Catalysts for Hydrodesulfurization and Hydrodeoxygenation written by Seyyedmajid Sharifvaghefi and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Problems associated with hydrotreating of heavy and extra-heavy crude oils in conventional fixed-bed reactors have led to the design of more innovative reactors such as slurry reactors. Dispersed fine catalysts are commonly used in slurry reactors. However, separation of the fine particles with sizes in micrometers or nanometers from the liquid phase represents a challenge. In this work, novel magnetically recyclable catalysts are designed to address this issue. Two different magnetic core materials, Fe3O4 and Fe3S4, were studied. Core-and-shell composite catalysts MoS2/Fe3O4 and MoS2/Fe3S4 were designed. Both catalysts showed high activity in the hydrodesulfurization (HDS) of dibenzothiophene (DBT). Former one showed high affinity towards the direct desulfurization (DDS) pathway while the later one presented a balanced selectivity between DDS and hydrogenation (HYD) pathways. This provides the refineries an option to adjust the hydrotreating process based on their needs using each of the catalysts or a combination of both. Catalyst MoS2/Fe3S4 was further promoted by nickel and cobalt. The activity of the catalysts could be ranked as NiMoS/Fe3S4 > CoMoS/Fe3S4 > MoS2/Fe3S4. Addition of Ni to MoS2 catalyst forms the Ni-Mo-S phase with increased accessible sulfur edge which is responsible for the enhancement in both hydrogenation and desulfurization. The catalyst MoS2 with greigite core and its promoted catalyst NiMoS/CoMoS were also applied to the hydrodeoxygenation (HDO) of stearic acid. HDO was the dominant pathway for all of the catalysts. Catalysts MoS2/Fe3O4 and MoS2/Fe3S4 were used to investigate the roles of H2 and H2S and the involved active sites in the HDS of DBT. Two different active sites for hydrogenation (HYD) and hydrodesulfurization (HDS) were identified. The MoS2 with magnetite core demonstrated high selectivity towards the DDS pathway, which was attributable to the differences in adsorption energy of hydrogen and DBT over hydrogenation and desulfurization sites. H2S is favored being adsorbed on the S-edge vacancies to transfer the active sites to HYD/Isomerization sites. Hydrogen plays three distinctive roles: 1) When adsorbed at Mo edge, hydrogen promotes hydrogenation; 2) Strongly bonded at S-edge it accounts for direct desulfurization; 3) while loosely bonded to S-edge it favors HYD and isomerization."--Pages ii-iii.
Download or read book Synthesis of Highly Active Unsupported Molybdenum Sulfide Catalysts for Hydrosulfurization and Hydrodeoxygenation written by Haiping Zhang and published by . This book was released on 2014 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The rigorous regulation on sulfur emission calls for newly designed catalysts with deep hydrodesulfurization capability. This has triggered a significant increase in research activities to seek suitable materials and synthesis techniques. Unsupported MoS2 becomes a good candidate as it possesses high catalytic activity and thermo stability. However, so far it is still a challenge to synthesize a dispersed MoS2 catalyst with low-cost precursors and simple methods. In this thesis, a novel hydrothermal method was developed using MoO3, Na2S, and HCl as precursors for the synthesis of unsupported MoS2. Several key factors that influence the catalyst synthesis and performance were carefully investigated, including the ratio of precursors, synthesis temperature, initial temperature, solvents, and promoters. Various characterization techniques, including XRD, TEM, SEM, XANES, EXAFS, Auto-sorb, TPR, microprobe analyzer, XPS, EDX, etc., were used to identify the crystalline structures of synthesized catalysts and to establish the relationship between their structures and hydrotreating activities. The hydrothermal synthesis method was successfully established. Results show that the weakly acidic medium is beneficial to the formation of MoS2. Proper MoO3/Na2S ratios lead to characteristics, such as nanocrystalline structure and large surface areas and pore volumes. Both the synthesis temperature and the initial temperature are key factors for the nucleation and growth of MoS2. A minimum synthesis temperature exists for the formation of crystalline structure, and high synthesis temperatures results in curved and shortened slabs. A high initial temperature benefits fast nucleation, thus leading to shorter slabs. Organic solvent (decalin) and supercritical heptane can dramatically change the aqueous environment. MoS2 slabs could be bent with the addition of decalin, and the curvature degree increases with the increase of decalin amounts. Supercritical heptane aids the creation of highly curved catalysts with better HDS performance (92.95% S conversion). The synthesized MoS2 catalysts were applied for the HDS of light cycle oil and for deoxygenation of waste cooking oil and canola oil to investigate the catalysis mechanisms. A new insight is proposed to distinguish the roles of promoters on deoxygenation pathways. NiMoS creates abundant sulfur vacancies that improve the hydrodeoxygenation, while CoMoS shows saturated edge sites in hydrogen atmosphere and facilitates the hydrodecarbon(x)ylation. From a kinetic model of deoxygenation process over CoMoS, it is found that direct hydrodecarbonylation of fatty acids dominates the hydrodecarbon(x)ylation routes; in the hydrodeoxygenation route, the reduction of fatty acids to alcohols is the rate limiting step in the production of C18 hydrocarbons from fatty acids."--Pages ii, iii.
Download or read book Chalcogenide Based Nanomaterials as Photocatalysts written by Mohammad Mansoob Khan and published by Elsevier. This book was released on 2021-04-07 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chalcogenide-Based Nanomaterials as Photocatalysts deals with the different types of chalcogenide-based photocatalytic reactions, covering the fundamental concepts of photocatalytic reactions involving chalcogenides for a range of energy and environmental applications. Sections focus on nanostructure control, synthesis methods, activity enhancement strategies, environmental applications, and perspectives of chalcogenide-based nanomaterials. The book offers guidelines for designing new chalcogenide-based nanoscale photocatalysts at low cost and high efficiency for efficient utilization of solar energy in the areas of energy production and environment remediation. Provides information on the development of novel chalcogenide-based nanomaterials Outlines the fundamentals of chalcogenides-based photocatalysis Includes techniques for heterogeneous catalysis based on chalcogenide-based nanomaterials
Download or read book Transition Metal Sulphides written by Th. Weber and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrotreating catalysis with transition metal sulphides is one of the most important areas of industrial heterogeneous catalysis. The present book deals with the chemical and catalytic aspects of transition metal sulphides, focusing on their use in hydrotreating catalysis. The book¿s 12 chapters present reviews of solid-state, coordination and organometallic chemistry, surface science and spectroscopic studies, quantum chemical calculations, catalytic studies with model and real catalysts, as well as refinery processes. A presentation of state-of-the-art background to pertinent work in the field. Can be used as an introduction to the chemical and catalytic properties of transition metal sulphides as well as an advanced level reference.
Download or read book Metal catalysis in Industrial Organic Processes written by Gian Paolo Chiusoli and published by Royal Society of Chemistry. This book was released on 2008 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: A definitive reference source, written by practising experts in the field, providing detailed and up-to-date information on key aspects of metal catalysis.
Download or read book Multiphase Catalytic Reactors written by Zeynep Ilsen Önsan and published by John Wiley & Sons. This book was released on 2016-06-09 with total page 399 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a holistic approach to multiphase catalytic reactors from their modeling and design to their applications in industrial manufacturing of chemicals Covers theoretical aspects and examples of fixed-bed, fluidized-bed, trickle-bed, slurry, monolith and microchannel reactors Includes chapters covering experimental techniques and practical guidelines for lab-scale testing of multiphase reactors Includes mathematical content focused on design equations and empirical relationships characterizing different multiphase reactor types together with an assortment of computational tools Involves detailed coverage of multiphase reactor applications such as Fischer-Tropsch synthesis, fuel processing for fuel cells, hydrotreating of oil fractions and biofuels processing
Download or read book Nontraditional Careers for Chemists written by Lisa M. Balbes and published by . This book was released on 2007 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Chemistry background prepares you for much more than just a laboratory career. The broad science education, analytical thinking, research methods, and other skills learned are of value to a wide variety of types of employers, and essential for a plethora of types of positions. Those who are interested in chemistry tend to have some similar personality traits and characteristics. By understanding your own personal values and interests, you can make informed decisions about what career paths to explore, and identify positions that match your needs. By expanding your options for not only what you will do, but also the environment in which you will do it, you can vastly increase the available employment opportunities, and increase the likelihood of finding enjoyable and lucrative employment. Each chapter in this book provides background information on a nontraditional field, including typical tasks, education or training requirements, and personal characteristics that make for a successful career in that field. Each chapter also contains detailed profiles of several chemists working in that field. The reader gets a true sense of what these people do on a daily basis, what in their background prepared them to move into this field, and what skills, personality, and knowledge are required to make a success of a career in this new field. Advice for people interested in moving into the field, and predictions for the future of that career, are also included from each person profiled. Career fields profiled include communication, chemical information, patents, sales and marketing, business development, regulatory affairs, public policy, safety, human resources, computers, and several others. Taken together, the career descriptions and real case histories provide a complete picture of each nontraditional career path, as well as valuable advice about how career transitions can be planned and successfully achieved by any chemist.
Download or read book Catalytic Hydrogenation for Biomass Valorization written by Roberto Rinaldi and published by Royal Society of Chemistry. This book was released on 2015 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the biorefinery industry expands to meet the latest discoveries in biomass conversion, this book provides a thorough grounding in the subject.
Download or read book Hydrocracking Science and Technology written by Julius Scherzer and published by CRC Press. This book was released on 1996-08-06 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents advances in the field of hydrocracking. The volume includes catalytic materials, reaction mechanisms and pathways, as well as hydrocracking processes and applications. It discusses hydrocracking processes and hydrocracking technology in catalytic dewaxing, resid upgrading, and fluid catalytic cracking feedstock improvement
Download or read book Iron and Cobalt Catalysts written by Wilson D. Shafer and published by MDPI. This book was released on 2020-06-23 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the turn of the last century when the field of catalysis was born, iron and cobalt have been key players in numerous catalysis processes. These metals, due to their ability to activate CO and CH, haev a major economic impact worldwide. Several industrial processes and synthetic routes use these metals: biomass-to-liquids (BTL), coal-to-liquids (CTL), natural gas-to-liquids (GTL), water-gas-shift, alcohol synthesis, alcohol steam reforming, polymerization processes, cross-coupling reactions, and photocatalyst activated reactions. A vast number of materials are produced from these processes, including oil, lubricants, waxes, diesel and jet fuels, hydrogen (e.g., fuel cell applications), gasoline, rubbers, plastics, alcohols, pharmaceuticals, agrochemicals, feed-stock chemicals, and other alternative materials. However, given the true complexities of the variables involved in these processes, many key mechanistic issues are still not fully defined or understood. This Special Issue of Catalysis will be a collaborative effort to combine current catalysis research on these metals from experimental and theoretical perspectives on both heterogeneous and homogeneous catalysts. We welcome contributions from the catalysis community on catalyst characterization, kinetics, reaction mechanism, reactor development, theoretical modeling, and surface science.
Download or read book Mobilizing the Russian Nation written by Melissa Kirschke Stockdale and published by Cambridge University Press. This book was released on 2016-12-13 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study of Russian mobilization in the Great War explores how the war shaped national identity and conceptions of citizenship.
Download or read book Photocatalytic Hydrogen Evolution written by Misook Kang and published by MDPI. This book was released on 2020-06-17 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Energy crises and global warming pose serious challenges to researchers in their attempt to develop a sustainable society for the future. Solar energy conversion is a remarkable, clean, and sustainable way to nullify the effects of fossil fuels. The findings of photocatalytic hydrogen production (PCHP) by Fujishima and Honda propose that “water will be the coal for the future”. Hydrogen is a carbon-free clean fuel with a high specific energy of combustion. Titanium oxide (TiO2), graphitic-carbon nitride (g-C3N4) and cadmium sulfide (CdS) are three pillars of water splitting photocatalysts owing to their superior electronic and optical properties. Tremendous research efforts have been made in recent years to fabricate visible or solar-light, active photocatalysts. The significant features of various oxide, sulfide, and carbon based photocatalysts for cost-effective hydrogen production are presented in this Special Issue. The insights of sacrificial agents on the hydrogen production efficiency of catalysts are also presented in this issue.
Download or read book Alternative Catalytic Materials written by Justin S J Hargreaves and published by Royal Society of Chemistry. This book was released on 2018-07-11 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many important industrial chemical processes rely heavily on catalysis and so researchers are always on the lookout for alternative catalytic materials that may improve existing processes or lead to new ones. Families of alternative catalytic materials currently being investigated include the carbides, nitrides and phosphides as well as amorphous boron catalysts. The addition of carbon, nitrogen or phosphorous to transition metals and the creation of boron-transition metal alloys leads to catalytic materials that have interesting properties, with applications in a range of different reactions, including electrocatalysis. This book provides a comprehensive account of the preparation, characterisation and application of these catalytic materials. It is an important reference for researchers and industrialists working in heterogeneous catalysis and materials chemistry.
Download or read book Fundamentals of Natural Fibres and Textiles written by Ibrahim H. Mondal and published by Woodhead Publishing. This book was released on 2021-03-20 with total page 817 pages. Available in PDF, EPUB and Kindle. Book excerpt: The textile industry is focused in its search for alternative green fibres with the aim of providing high-quality products which are fully recyclable and biodegradable. Natural textile materials from renewable sources play an increasingly important role in the industry due to their unique properties and functionality over synthetic fibres, as well as their sustainability. Fundamentals of Natural Fibres and Textiles covers all the fundamental and basic information about natural fibres and textiles. Many different fibres are covered from their origin, through processing, properties, and applications. The latest methods for characterisation and testing of natural fibres are all addressed with reference to cutting-edge industry trends. This uniquely comprehensive approach to the topic provides the ideal entry point to natural fibres for textile and clothing scientists, engineers, designers, researchers, students, and manufacturers of such products. Explains the characteristics of natural fibres to show how they compare to synthetic fibres for a range of purposes Provides an overview of the environmental impact of the processing of fibres and how this creates industrial waste Covers a wide range of natural fibres in detail, from traditional silk and wool to electrospun biopolymers Provides the latest updates on technologies for designing natural fibres and applying them to the development of new products
Download or read book Transmission Electron Microscopy written by C. Barry Carter and published by Springer. This book was released on 2016-08-24 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text is a companion volume to Transmission Electron Microscopy: A Textbook for Materials Science by Williams and Carter. The aim is to extend the discussion of certain topics that are either rapidly changing at this time or that would benefit from more detailed discussion than space allowed in the primary text. World-renowned researchers have contributed chapters in their area of expertise, and the editors have carefully prepared these chapters to provide a uniform tone and treatment for this exciting material. The book features an unparalleled collection of color figures showcasing the quality and variety of chemical data that can be obtained from today’s instruments, as well as key pitfalls to avoid. As with the previous TEM text, each chapter contains two sets of questions, one for self assessment and a second more suitable for homework assignments. Throughout the book, the style follows that of Williams & Carter even when the subject matter becomes challenging—the aim is always to make the topic understandable by first-year graduate students and others who are working in the field of Materials Science Topics covered include sources, in-situ experiments, electron diffraction, Digital Micrograph, waves and holography, focal-series reconstruction and direct methods, STEM and tomography, energy-filtered TEM (EFTEM) imaging, and spectrum imaging. The range and depth of material makes this companion volume essential reading for the budding microscopist and a key reference for practicing researchers using these and related techniques.
Download or read book Handbook of Petroleum Processing written by Steven A. Treese and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bismuth Ferrite Based Electrochemical Supercapacitors written by Vijaykumar V. Jadhav and published by Springer Nature. This book was released on 2020-05-15 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a much-needed, up-to-date overview of unary, binary and ternary bismuth-ferrite-based systems, with a focus on their properties, synthesis methods and applications as electrochemical supercapacitors. It introduces readers to the basic structure and properties of ferrites in general, focusing on the selection criteria for ferrite materials for electrochemical energy storage applications. Along with coverage of ferrite synthesis methods, it discusses bismuth-ferrite structures in unary, binary and mixed ferrite nanostructure systems, as well as future perspectives and limitations for using ferrites as electrochemical supercapacitors. A valuable resource for beginners and advanced researchers working on similar topics, this book enables them to understand the core materials and electrochemical concepts behind bismuth-ferrite-based systems as energy storage materials.
