Download or read book Tuning Palladium Selective Oxidation Catalysts Via Mesoporous Supports written by Christopher Michael A. Parlett and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Surfactant templating provides a facile route to mesoporous materials with tuneable architectures, whilst simultaneously allowing control over complementary macro and micro porosity. The impact of these varying physical properties, on both catalyst synthesis and during catalytic reactions, was one principal area of investigation. Catalyst series were prepared on mesoporous SBA-15, SBA-16 and KIT-6, meso-macroporous SBA-15, true liquid crystal templated SBA-15 and a commercial low surface area silica support. Additionally two mesoporous alumina series, with mesoporosity akin to SBA-15, were produced. The catalytic activity of the materials was screened for the selective oxidation of allylic alcohols, which represents a class of industrially relevant chemical upgrading reactions. Nanoparticulate palladium is widely recognised as an able catalytic species, although the active site nature is still debated with both metallic and oxidic surfaces proposed. Further insight into the active species was another major area of investigation. Extensive characterisation confirmed successful support synthesis and mesopore stability after palladium impregnation. Irrespective of support, decreasing metal loading elevates dispersion (particles sizes are typically less than 2nm), which correlates with the increase of surface PdO content. In relation to the silica supports these trends escalate via support transition in the order of: Pd/low surface area commercial silica

Download or read book XAFS Techniques for Catalysts Nanomaterials and Surfaces written by Yasuhiro Iwasawa and published by Springer. This book was released on 2016-10-19 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive, theoretical, practical, and thorough guide to XAFS spectroscopy. The book addresses XAFS fundamentals such as experiments, theory and data analysis, advanced XAFS methods such as operando XAFS, time-resolved XAFS, spatially resolved XAFS, total-reflection XAFS, high energy resolution XAFS, and practical applications to a variety of catalysts, nanomaterials and surfaces. This book is accessible to a broad audience in academia and industry, and will be a useful guide for researchers entering the subject and graduate students in a wide variety of disciplines.

Download or read book Preparation of Catalysts VII written by R. Maggi and published by Elsevier. This book was released on 1998-08-17 with total page 1007 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proceedings of the VIIth International Symposium on the Scientific Bases for the Preparation of Heterogeneous Catalysts, are in line with the general scope of this series of events. Emphasis in all Symposia has been on the scientific aspects of the preparation of new and industrial catalysts, or on new methods of preparation, rather than on the catalytic reactions in which such solids are ultimately used. In the present context, the catalytic event itself has only been considered as another, though often decisive, method of catalyst characterization.

Download or read book Heterogeneous Gold and Palladium Based Catalysts for Solvent free Oxidation of Toluene written by Mohd Izham Bin Saiman and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalyzed oxidation of aromatic hydrocarbons with molecular oxygen has been studied for several decades. For example, toluene can be converted into oxidation products such as benzyl alcohol, benzaldehyde, benzoic acid and benzyl benzoate. At present, the principal industrial production of benzoic acid via the oxidation of toluene involves the use of homogeneous cobalt catalysts in an air pressurized aqueous acetic acid mixture in the presence of Mn ions. However, the use of solvent causes difficulties in the separation of catalysts and products, equipment corrosion, and due to the environmental hazards associated with the use of liquid acids as solvent. Developing solvent free toluene oxidation having great activity has attracted special attention as a promising environmentally friendly reaction. Recently, gold based supported catalyst have been found to be highly effective oxidation catalyst where a number of important discoveries have been made such as in hydrogen peroxide synthesis and selective oxidation of alcohols to aldehydes. As a proof of concept for the following studies, oxidation of toluene and other aromatic hydrocarbons were carried out in round bottom flask with TBHP as oxidant. At mild condition (80 oC), it was evident that Au-Pd supported catalyst is capable of oxidising aromatics C-H bonds on toluene and derivatives and TBHP as oxidant also have been discovered well in this thesis. The catalyst preparation method was shown to be very important in the formation of active site catalysts. The sol-immobilisation catalyst with a narrow distribution of small particles, was more active than Au-Pd alloy having Au-core palladium shell with PdO dominance on the surface via impregnation catalyst. In addition to that, the choice of support is crucial and this study discovered carbon as a preferred support give enhance on performance activity of toluene. At the same time, the distribution of products can be altered with the choice of preparation methods and support. The synergistic effect of Au and Pd was confirmed by superior catalytic activity compared to monometallic catalyst. Investigations of reaction conditions such as reaction time, reusability, pre-treatment conditions, metal ratio, and mass of catalyst were fully investigated. It was found that the activity and selectivity of the catalyst was highly dependent on these variables. Reaction mechanism was proposed and it was based on catalytic evaluation data. Even though, the proposed mechanism was contradicted by the EPR data study, it was believed that the reactive oxygen species (ROS) was involved in the surface of catalyst and give effect of the catalytic activity. Overall, the oxidation of toluene was successfully studied by using Au-Pd supported catalyst and can not be denied that the importance of TBHP as oxidant involve in this process has been proven.

Download or read book New and Future Developments in Catalysis written by P. Štěpnička and published by Elsevier Inc. Chapters. This book was released on 2013-07-18 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tuning Metal support Interaction for Catalysis at Multi component Interfaces written by Shyam Deo and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The enhancement of catalytic activity is often attributed to special sites along a metal-oxide boundary, where an adsorbed species interacts with both the metal and the support. Indeed, such "dual" reaction sites often with emergent chemical properties have been implicated as the active sites for many chemical reactions, whether it be simpler molecular reactions such as CO oxidation and water-gas shift or far more complex reaction pathways such as de-oxygenation of multi-oxygenated reactants like furfuryl alcohol, m-cresol etc. Moreover, close connections of synthesis, characterization, kinetic testing, and computational modeling can enable researchers to tailor metal/metal-oxide catalytic systems towards such complex catalytic requirements. In this thesis, computational catalysis techniques are integrated with experimental efforts of collaborators to investigate two catalytic reactions: furfural hydrodeoxygenation (HDO) to methyl furan and CO oxidation. Experimental works motivate a series of research questions and hypotheses, towards connecting multi-component (oxide-metal) catalytic site properties to catalytic performance. In particular, Density Functional Theory (DFT) has been used in combination with experimental characterization and reactivity studies to underline the principles governing the potentials and design of multi-component catalytic systems. HDO of furfuryl alcohol was examined using a DFT model of a metal/TiO2 nanowire interface. Redox functionality of the metal oxide aids in breaking the C-O bond of the alcohol, while the metal facilitates C-H formation to the final product, 2-methylfuran. In addition to this "bifunctionality", electron transfer between the oxide and the metal alters reactivity, suggesting emergent chemical properties unique to the interface. Our DFT results were used to explain experimental observations of enhanced selectivity for TiO2-coated Pd nanoparticles. We have also successfully extended our TiO2/Pd interface model, altering the composition of this interface to develop a set of descriptors that predict optimal HDO activity at the metal oxide/metal interface. Low-temperature CO oxidation was examined over CeO2 supported single atoms, a probe for determining the synergetic roles of single metal atom catalysts (SACs) and redox active supports. The redox states involved in catalytic oxidation cycles on SACs are not well-determined and limit rational design of these catalytic systems. Experimental characterization observes only "resting states" of SACs, whereas DFT and microkinetic studies can be used to reconcile a full redox cycle. We addressed these challenges by developing a first principles microkinetic model and reconciling elementary step reaction kinetics with experimentally measured reaction orders and activation barriers. We calibrated the microkinetic model through Bayesian statistical inference approach to include the error in both DFT calculated energetics and experimental measurements in mechanism determination. This approach successfully elucidated reaction mechanisms and identified dominant reaction networks to directly match experimental reaction orders and barriers. Combining experiment and modeling, we demonstrated role of metal oxidation states with their reactivity for oxidation catalysis, indicating that the unique oxidation activity of these catalysts arises from the relatively close stability of the wide range of oxidation states achieved through synergistic interaction with metal oxides. In addition, to achieve proper active site environment over the oxide supports, a careful and controlled adsorption of ionic and/or hydrated metal precursors over the surface is essential during synthesis, therefore we also briefly examine synthesis rules for catalysts with precise control over size and uniformity in dispersion with specific potential to generate singly adsorbed metal catalysts over oxides. In short, these works combinedly demonstrate how metal/metal oxide catalytic systems can be used to improve heterogeneous catalytic activity and selectivity for important energy conversion processes, and further on, the broader perspective of active sites design along the metal and oxide boundaries for oxidation and reduction catalysis.

Download or read book Liquid phase Selective Hydrogenation of Phenylacetylene on Palladium Nanoparticles Supported on Mesoporous Silica written by and published by . This book was released on 2009 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of palladium catalysts with ca. 1 wt% palladium supported on mesoporous silica with different pore sizes (MCM-41, SBA-15, and MCF) were prepared by deposition of colloidal Pd nanoparticles (Pd/X_col) and Pd(II)acetate solution (Pd/X_imp). MCM-41 and SBA-15 showed the XRD characteristic peaks indicating highly ordered hexagonal pore structure while MCF consisted of spherical cell and frame structure with average pore size of 2.7, 3.9, and 7.8 nm, respectively. Sizes of the colloidal Pd nanoparticles were about 2.3 nm. The supports pore structure did not affect the Pd particle size of Pd/X_col catalysts. For the Pd/X_imp, the Pd particle size was increased with increasing pore diameter of the supports. However, the largest Pd particle size was obtained on Pd/SBA-15_imp since the Pd particles were formed in a long cylindrical shape similar to SBA-15. The Pd/SBA-15_col exhibited the best catalyst performance in the liquid-phase selective hydrogenation of phenylacetylene under mild conditions (40 degress celsius, H2 pressure = 1-5 bar, 30 min). The appropriated pore structure and pore size of SBA-15 could provide a better encapsulation of Pd particles so that high styrene selectivity was attained at complete conversion of phenylacetylene. All the Pd/X_col catalysts exhibited no change in the catalyst activities/selectivity during the recyclability test for four cycles while the Pd/X_imp showed an increase of catalyst activity and lower styrene selectivity in some cases.

Download or read book Scientific Bases for the Preparation of Heterogeneous Catalysts written by E. Gaigneaux and published by Elsevier. This book was released on 2002-08-29 with total page 1150 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has become a tradition that every four years, the Université Catholique de Louvain and the Katholieke Universiteit Leuven jointly organize a symposium devoted to the scientific bases for the preparation of heterogeneous catalysts. These meetings bring together researchers from academia and industry and offer a forum for discussions on the chemistry involved in the preparation of industrial heterogeneous catalysts. This volume containing the Proceedings of the 8th International Symposium on Scientific Bases for the Preparation of Heterogeneous Catalysts consists of papers summarizing most of the 139 oral communications and posters selected by the international scientific committee, composed of 27 experts in the field of catalyst preparation, holding an industrial or academia appointment. The contributions focus on the aspects of catalyst preparation. The main topics are: new approaches in catalyst preparation; advanced preparations of nanoporous and mesoporous catalysts; catalysts preparation for special performances and purposes; catalysts for environmental purposes; and molecular catalysis. Emphasis is put on the role that catalysis can play as an essential element of sustainable development.

Download or read book Suzuki Miyaura Cross Coupling Reaction and Potential Applications written by Ioannis D. Kostas and published by MDPI. This book was released on 2018-03-23 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Suzuki–Miyaura Cross-Coupling Reaction and Potential Applications" that was published in Catalysts

Download or read book Chemical Catalysts for Biomass Upgrading written by Mark Crocker and published by John Wiley & Sons. This book was released on 2020-03-09 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive reference to the use of innovative catalysts and processes to turn biomass into value-added chemicals Chemical Catalysts for Biomass Upgrading offers detailed descriptions of catalysts and catalytic processes employed in the synthesis of chemicals and fuels from the most abundant and important biomass types. The contributors?noted experts on the topic?focus on the application of catalysts to the pyrolysis of whole biomass and to the upgrading of bio-oils. The authors discuss catalytic approaches to the processing of biomass-derived oxygenates, as exemplified by sugars, via reactions such as reforming, hydrogenation, oxidation, and condensation reactions. Additionally, the book provides an overview of catalysts for lignin valorization via oxidative and reductive methods and considers the conversion of fats and oils to fuels and terminal olefins by means of esterification/transesterification, hydrodeoxygenation, and decarboxylation/decarbonylation processes. The authors also provide an overview of conversion processes based on terpenes and chitin, two emerging feedstocks with a rich chemistry, and summarize some of the emerging trends in the field. This important book: -Provides a comprehensive review of innovative catalysts, catalytic processes, and catalyst design -Offers a guide to one of the most promising ways to find useful alternatives for fossil fuel resources -Includes information on the most abundant and important types of biomass feedstocks -Examines fields such as catalytic cracking, pyrolysis, depolymerization, and many more Written for catalytic chemists, process engineers, environmental chemists, bioengineers, organic chemists, and polymer chemists, Chemical Catalysts for Biomass Upgrading presents deep insights on the most important aspects of biomass upgrading and their various types.

Download or read book Solvent Free Methods in Nanocatalysis written by Rafael Luque and published by John Wiley & Sons. This book was released on 2023-04-10 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solvent-Free Methods in Nanocatalysis Discover solvent-free approaches for the synthesis of nanocatalysts as well as various catalytic transformations in this unique one-stop resource Solvent-free methods have attracted wide attention in organic synthesis and catalysis as a promising approach towards “greener” and more sustainable chemical transformations. In this regard, nanocatalysis has seen particular growth in recent years. Solvent-Free Methods in Nanocatalysis gives an in-depth overview of nanocatalysts and their catalytic applications using solvent-free methods. After a brief introduction, it covers various synthetic techniques for the preparation of nanocatalysts and supports using solvent-free methods, e.g. ball-milling, microwave- and plasma-assisted methods. The book discusses in detail different catalyst classes, such as metal oxides, doped and functionalized nanocarbons, as well as nitride- and silica-based materials to help researchers to understand the efficiency and nature of these catalysts/supports based on their chemical structure. In the book readers will also find: A brief account of the history, challenges, and recent advances in the field Detailed discussion of advantages and disadvantages of solvent-free techniques for nanocatalyst preparation Treatment of important solvent- and catalyst-free organic transformations (i.e. oxidation, coupling and multicomponent reactions) A chapter on supported ionic liquids for solvent-free catalysis Written by leading researchers in the field, Solvent-Free Methods in Nanocatalysis is a useful reference for researchers and students working in organic synthesis, catalysis, and nanomaterials science.

Download or read book Nanostructured Catalysts for Environmental Applications written by Marco Piumetti and published by Springer Nature. This book was released on 2021-01-20 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers an overview of the recent studies and advances in environmental catalysis by nanomaterials, considering both the fundamental and the technological aspects. It offers contributions in different areas of environmental catalysis, including the catalytic and photocatalytic abatement of environmentally hazardous effluents from stationary or mobile sources, the valorization of waste and the production of sustainable energy. In other words, this monograph provides an overview of modern environmental and energy related applications with a particular emphasis to nano-sized catalytic materials. Recent concepts, experimental data and advanced theories are reported in this book to give evidence of the environmental and sustainable applications that can be found in the highly interdisciplinary field of catalysis.

Download or read book Selective Oxidation of Allylic Alcohols on Palladium Catalysts written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gold Catalysis written by Laura Prati and published by CRC Press. This book was released on 2016-01-05 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the first report on alcohol oxidation in 1998, many studies have highlighted some peculiarity of gold with respect to other metals. Some analogies have been found between gas and liquid phases, but the big challenge to operate in a condensed phase lies in the role of the solvent in tuning the reactant-catalyst contact. Liquid-phase oxidation

Download or read book Catalytic Application of Gold and Palladium Nanoparticles Supported on Mesoporous Transition Metal Oxides in Oxidation and Hydrogenation Reactions written by Lizza Mpho Maponya and published by . This book was released on 2021 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ideas in Chemistry and Molecular Sciences written by Bruno Pignataro and published by John Wiley & Sons. This book was released on 2010-04-16 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by some of the most talented young chemists in Europe, this text covers most of the groundbreaking issues in materials science. It provides an account of the latest research results in European materials chemistry based on a selection of leading young scientists participating in the 2008 European Young Chemists Award competition. The contributions range from nanotechnology to catalysis. In addition, the authors provide a current overview of their field of research and a preview of future directions. For materials scientists, as well as organic and analytical chemists.

Download or read book Nanoscale Graphitic Carbon Nitride written by Alagarsamy Pandikumar and published by Elsevier. This book was released on 2021-09-03 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoscale Graphitic Carbon Nitride focuses on multi-functional applications including energy conversion, storage and healthcare. Polymeric graphitic carbon nitride materials have attracted much attention in recent years because of their similarity to graphene. They are composed of carbon, nitrogen and some minor hydrogen content. In contrast to graphene, g-Graphitic carbon nitride is a medium band-gap semiconductor and in that role an effective photocatalyst and chemical catalyst for a broad variety of reactions and applications. This book covers the fundamentals and applications of graphitic carbon nitride (g-C3N4) in different sectors. It also covers the application of graphitic carbon nitride-based composites with metal, metal oxides, metal sulphide and carbon-based materials. This is an important resource for researchers in the fields of materials science, engineering, energy storage and chemical engineering who want to understand how nanoscale graphitic carbon nitride is being used for a range of industrial applications and processes. Outlines the major properties of nanoscale graphitic carbon nitride, along with their major application areas Assesses the challenges of manufacturing graphitic carbon nitride on a mass scale Explains major synthesis methods for nanoscale graphitic carbon nitride