Download or read book Structure activity Correlations in Alumina Supported Palladium Catalysts written by Tim Lear and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Alumina Grinding on the Properties of Alumina Supported Palladium Catalysts in Selective Hydrogenation of Acetylene written by and published by . This book was released on 2008 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the effects of alumina grinding and mixed oxides (ZnO-Al2O3 and NiO-Al2O3) grinding with various Zn/Al and Ni/Al molar ratios (0.1 and 0.5) prepared by an attrition ball mill on catalytic performance of alumina supported Pd catalysts for selective hydrogenation of acetylene were investigated. It was found that catalytic performances of the Pd catalyst supported on Al2O3 milled for 12 h were superior compared to those of Pd-supported on the unmilled Al2O3. However, all the catalysts prepared from milled mixed oxides presented lower acetylene conversion and ethylene selectivity than that of the catalyst prepared from alumina milled for 12 h. From X-ray diffraction, it was suggested that varying milling time directly affected the crystallite size, surface area and acidity of alumina supports. As revealed by CO chemisorption, milling of Al2O3 supports could increase metal active sites of Pd/Al2O3 catalysts without change in the interaction between Pd and the alumina support so that the catalysts exhibited higher acetylene activity and ethylene selectivity. Moreover, increasing of acidity affected coke formation on the catalysts.
Download or read book An Investigation of Methane Combustion Over Modified Alumina Supported Palladium Catalysts written by Matthew David Davies and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Combustion of Methane Over Alumina Supported Palladium written by Maxim R. Lyubovsky and published by . This book was released on 1999 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Frontiers in Catalysis written by L. Guczi and published by . This book was released on 1993 with total page 1004 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physical and surface characteristics of alumina supported platinum and palladium catalysts for isotopic exchange between hydrogen and water written by J. H. Rolston and published by . This book was released on 1971 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis Characterization and Activity of Palladium Catalysts on the Dual Support of Cerium and Aluminum Oxides written by Jihyeon Park and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of sequence of impregnation (Pd on cerium oxides -alumina and cerium oxides on Pd-alumina) and calcination temperature (500 °C and 850 °C) on the catalytic oxidation of methane under lean conditions were investigated. The catalysts were prepared by a combination of impregnation, slurry and vortexing methods. The catalysts had 4.7 wt.% Pd and 10.7 wt.% Ce based on inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. The catalysts were characterized by pulse chemisorption, temperature programmed reduction (TPD), scanning transmission electron microscopy (STEM), and X-ray photoelectron spectroscopy (XPS). The activity of the catalysts for methane combustion was measured in a fixed-bed flow reactor by flowing a gas mix (0.98 vol % methane, 4.01 vol % and balance nitrogen) through a catalytic bed. The temperature of the catalytic bed was controlled by a temperature -controlled tube furnace. The % methane in the effluent gas mix was measured by a gas chromatograph fitted with a flame ionization detector and a ‘Carbon Plot’ column. Palladium was present as PdO and PdOx x>2+ and cerium as CeOx (+3 and +4 oxidation states) as per XPS analysis. The activity of the Pd/cerium oxides-alumina500C catalyst was higher than the cerium oxides/Pd-alumina500C catalyst at 250-500 °C. Similar trends in the activity were seen for the two catalysts calcined at 850 °C. Higher dispersion and lower particle size, and the presence of small Pd particles on alumina accounted for the higher catalytic activities of the Pd/cerium oxides-alumina500C and 850C catalysts. The lower activities of cerium oxides/Pd-alumina500C and 850C were primarily due to the embedment of Pd onto ceria due to strong PdO-CeOx interactions. This research implies that the sequence of impregnation and calcination temperature could alter catalytic properties and activity for methane combustion through PdO/PdOx -support interactions.
Download or read book Characterization of Solid Materials and Heterogeneous Catalysts written by Michel Che and published by John Wiley & Sons. This book was released on 2012-04-16 with total page 1313 pages. Available in PDF, EPUB and Kindle. Book excerpt: This two-volume book provides an overview of physical techniques used to characterize the structure of solid materials, on the one hand, and to investigate the reactivity of their surface, on the other. Therefore this book is a must-have for anyone working in fields related to surface reactivity. Among the latter, and because of its most important industrial impact, catalysis has been used as the directing thread of the book. After the preface and a general introduction to physical techniques by M. Che and J.C. Vedrine, two overviews on physical techniques are presented by G. Ertl and Sir J.M. Thomas for investigating model catalysts and porous catalysts, respectively. The book is organized into four parts: Molecular/Local Spectroscopies, Macroscopic Techniques, Characterization of the Fluid Phase (Gas and/ or Liquid), and Advanced Characterization. Each chapter focuses upon the following important themes: overview of the technique, most important parameters to interpret the experimental data, practical details, applications of the technique, particularly during chemical processes, with its advantages and disadvantages, conclusions.
Download or read book Solid Base Catalysis written by Yoshio Ono and published by Springer Science & Business Media. This book was released on 2012-08-31 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of solid base catalysts has come to be recognized for their environmentally benign qualities, and much significant progress has been made over the past two decades in catalytic materials and solid base-catalyzed reactions. The book is focused on the solid base. Because of the advantages over liquid bases, the use of solid base catalysts in organic synthesis is expanding. Solid bases are easier to dispose than liquid bases, separation and recovery of products, catalysts and solvents are less difficult, and they are non-corrosive. Furthermore, base-catalyzed reactions can be performed without using solvents and even in the gas phase, opening up more possibilities for discovering novel reaction systems. Using numerous examples, the present volume describes the remarkable role solid base catalysis can play, given the ever increasing worldwide importance of "green" chemistry. The reader will obtain an overall view of solid base catalysis and gain insight into the versatility of the reactions to which solid base catalysts can be utilized. The concept and significance of solid base catalysis are discussed, followed by descriptions of various methods for the characterization of solid bases, including spectroscopic methods and test reactions. The preparation and properties of base materials are presented in detail, with the two final chapters devoted to surveying the variety of reactions catalyzed by solid bases.
Download or read book Molecular Spectroscopy of Oxide Catalyst Surfaces written by Anatoli Davydov and published by John Wiley & Sons. This book was released on 2003-06-27 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt: As in the study of transition metal complexes in solution, molecular spectroscopic methods - principally the infrared, ultraviolet/visible and electron spin resonance spectroscopies - have played key roles in establishing the concepts of coordination chemistry occurring at the surfaces of solids. This book describes the development of the principals of coordination chemistry of oxide surfaces using analyses of data obtained by these methods. The nature, properties, concentration of the surface adsorption centers and their influence on the character of interaction with different molecules are investigated. The book commences with an account of the basic theoretical principles and experimental techniques of the various spectroscopy methods, with special attention devoted to in situ measurements where the oxide or catalyst sample is in contact with the adsorbate or the reactant. A detailed account is presented of the methods for characterizing the oxidation state and degree of coordination of surface cations and oxygen anions by the adsorption of probe molecules. The complexation of many inorganic, organometallic and organic molecules with different oxide systems is critically examined, and a classification of formed surface compounds, based on the interaction with definite type of adsorption centers, is given. Possible mechanisms of numerous catalytic reactions, including the transformation of organic molecules over acidic catalysts via the carboionic mechanism, are discussed using the spectroscopic identifications of reaction intermediates. A comprehensive analysis of the literature on the interpretation of the spectra of surface compounds on oxides is presented. This highly illustrated and extensively referenced volume is intended for specialists working in the fields of surface physical chemistry, surface and materials sciences, and adsorption phenomena and is essential reading for those involved in the heterogeneous catalysis by transition metal-oxides.
Download or read book Investigating the Effects of Pdn Cluster Size and the Alumina Support Thickness on the Electronic Structure Geometry and Catalytic Activity Probed Via the Co Oxidation Reaction written by Matthew David Kane and published by . This book was released on 2014 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atmospheric Chemistry and Physics of Air Pollution written by John H. Seinfeld and published by Wiley-Interscience. This book was released on 1986 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fundamental treatment of all aspects of the physical and chemical behavior of air pollutants. Provides a clear analysis of the chemistry of atmospheric pollutants, an extensive treatment of the formation, thermodynamics and dynamics of atmospheric aerosols, and an elementary discussion of atmospheric diffusion with commonly used atmospheric diffusion formulas derived from first principles. Also contains comprehensive coverage of atmospheric removal processes, including wet and dry deposition; statistical distributions of atmospheric concentrations, and a discussion of acid rain. Numerous problems enable students to evaluate their understanding. All major chapters contain up-to-date bibliographies.
Download or read book Correlations Between Surface Structure and Catalytic Activity written by and published by . This book was released on 1992 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Objective is to address the keys to understanding the relation between surface structure and catalytic activity/selectivity. Of concern are questions related to enhanced catalytic properties of mixed-metal catalysts and critical active site requirements for molecular synthesis and rearrangement. The experimental approach utilizes a microcatalytic reactor contiguous to a surface analysis system, an arrangement which allows in vacuo transfer of the catalyst from one chamber to the other. Surface techniques being used include Auger (AES), UV and X-ray photoemission spectroscopy (UPS and XPS), temperature programmed desorption (TPD), low energy electron diffraction (LEED), high resolution electron energy loss spectroscopy (HREELS) and infrared reflection-absorption spectroscopy (IRAS). Our research program builds upon our previous experience relating the results of single crystal kinetic measurements with the results obtained with supported analogs. As well we are exploiting our recent work on the preparation, the characterization, and the determination of the catalytic properties of ultra-thin metal and metal oxide films. The program is proceeding toward the study of the unique catalytic properties of ultrathin metal films; the investigation of the critical ensemble size requirements for principal catalytic reaction types; and the modelling of supported catalysts using ultra-thin planar oxide surfaces.
Download or read book Structure Activity Correlations of Vanadium and Molybdenum Oxide Catalysts Supported on Nanostructured Materials written by and published by . This book was released on 2014 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Surface and Interface Science Volumes 5 and 6 written by Klaus Wandelt and published by John Wiley & Sons. This book was released on 2016-03-14 with total page 1532 pages. Available in PDF, EPUB and Kindle. Book excerpt: In eight volumes, Surface and Interface Science covers all fundamental aspects and offers a comprehensive overview of this research area for scientists working in the field, as well as an introduction for newcomers. Volume 5: Solid-Gas Interfaces I Topics covered: Basics of Adsorption and Desorption Surface Microcalorimetry Adsorption of Rare Gases Adsorption of Alkali and Other Electro-Positive Metals Halogen adsorption on metals Adsorption of Hydrogen Adsorption of Water Adsorption of (Small) Molecules on Metal Surfaces Surface Science Approach to Catalysis Adsorption, Bonding and Reactivity of Unsaturated and Multifunctional Molecules Volume 6: Solid-Gas Interfaces II Topics covered: Adsorption of Large Organic Molecules Chirality of Adsorbates Adsorption on Semiconductor Surfaces Adsorption on Oxide Surfaces Oscillatory Surface Reactions Statistical Surface Thermodynamics Theory of the Dynamics at Surfaces Atomic and Molecular Manipulation
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 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.
