Download or read book Characterization of Gold Catalysts for Methanol Synthesis written by Tracey Van Heerden and published by . This book was released on 2012 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: The activity (per mass of catalyst) of supported gold catalysts across a range of reduction and oxidation reactions is significantly affected by the average crystallite size of the gold crystallites in the catalyst. Supported gold catalysts are most commonly characterized for particle size using TEM and XRD. Both of these methods can have a large degree of inaccuracy associated with them at low metal loadings and for catalysts containing small gold crystallites. In this study oxygen chemisorption was used as an additional method to characterize supported gold catalysts to complement electron microscope techniques. Agreement between the results from these different methods was obtained only with regard to the order of magnitude range of crystallite size. The oxygen chemisorption can be used to estimate the mass fraction of gold present as nano-crystallites (typically less than 1%) implying a large room for improvement in catalyst preparation technique. In this study a range of supported gold catalysts were prepared by ion exchange, varying a range of preparation variables, including gold concentration in the precursor solution, washing procedure using an aqueous ammonia solution, as well as drying and calcination procedures. The washing procedure and in particular the concentration of ammonia and the duration affected the final metal loading of the catalyst. TEM analyses show crystallite size distributions between 2-5nm for all catalysts excepting those which were not washed using an aqueous ammonia solution and which did not show any small crystallites. Only the total omission of the ammonia wash resulted in a significant change in the gold crystallite sizes observed on TEM-images. Further characterization with SEM showed that catalysts that appeared identical on the TEM-images also contained large 50-500nm crystallites. This additional method of characterisation using SEM allowed for the identification of significant differences between catalysts upon varying the preparation methods. Catalyst drying was also shown to be a crucial step in the catalyst preparation method, with SEM images displaying only small well-distributed gold crystallites for catalysts dried in the rotary evaporator. Two of the catalysts were then tested for their activity and selectivity in the hydrogenation of CO or CO 2. Although it has been shown that the production of methanol from CO (and CO 2) can be catalysed by gold particles with crystallite sizes below 5nm (Haruta, 1997), this reaction has received comparatively little attention compared to the more extensively studied CO oxidation reaction. Testing was done over a range of temperatures (200 - 350°C) at a pressure of 30bar. The obtained methanol yields and selectivities are comparable to reported values in literature. The hydrogenation of CO 2 was shown to have higher yields and selectivities to methanol than the hydrogenation of CO over the same catalyst. The preparation of the catalyst was shown to have an effect on the activity and selectivity, with the catalyst dried in the rotary evaporator having a higher yield and selectivity to methanol, while also forming a larger variety of products than the catalyst dried in the oven.
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 Nano Gold Catalysts written by Neeraj Kumar Mishra and published by BoD – Books on Demand. This book was released on 2016-08-31 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gold, considered catalytically inactive for a long time, is now a fascinating partner of modern chemistry, as scientists such as Bond, Teles, Haruta, Hutchings, Ito and Hayashi opened new perspectives for the whole synthetic chemist community. Recently gold has attracted significant attention due to its advantageous characteristics as a catalytic material and since it allows easy functionalization with biologically active molecules. In this context, when gold is prepared as very small particles, it turns out to be a highly active catalyst. However, such a phenomenon completely disappears when the gold particle size grows into the micrometer range. Therefore, the preparation for obtaining an active gold catalyst is so important. The primary objective of this book is to provide a comprehensive overview of gold metal nanoparticles and their application as promising catalysts.
Download or read book Preparation and Characterization of Ternary Cu Catalysts for Methanol Synthesis written by Stefan Kaluza and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CeO2 supported Gold Catalysts for CO Oxidation written by Veronica Illeana Aguilar-Guerrero and published by . This book was released on 2008 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Bimetallic Platinum gold Catalysts written by Corina Mihut and published by . This book was released on 2002 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalysis by Gold written by Geoffrey Colin Bond and published by World Scientific. This book was released on 2006 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gold has traditionally been regarded as inactive as a catalytic metal. However, the advent of nanoparticulate gold on high surface area oxide supports has demonstrated its high catalytic activity in many chemical reactions. Gold is active as a heterogeneous catalyst in both gas and liquid phases, and complexes catalyse reactions homogeneously in solution. Many of the reactions being studied will lead to new application areas for catalysis by gold in pollution control, chemical processing, sensors and fuel cell technology. This book describes the properties of gold, the methods for preparing gold catalysts and ways to characterise and use them effectively in reactions. The reaction mechanisms and reasons for the high activities are discussed and the applications for gold catalysis considered. Sample Chapter(s). Chapter 1: Introduction to Catalysis (892 KB). Contents: Introduction to Catalysis; The Physical and Chemical Properties of Gold; Physical Properties and Characterisation of Small Gold Particles; Preparation of Supported Gold Catalysts; Chemisorption of Simple Molecules on Gold; Oxidation of Carbon Monoxide; The Selective Oxidation of Carbon Monoxide; Selective Oxidation; Reactions Involving Hydrogen; The WaterOCoGas Shift; Reactions of Environmental Importance; Catalysis by Soluble and Supported Gold Compounds; Miscellaneous Reactions Catalysed by Gold; Commercial Applications. Readership: Postgraduate level researchers in academia and industry, as well as general readers."
Download or read book Synthesis Modification and Characterization of Supported Gold Catalysts for Selective Hydrogenation of Acetylene in Presence of Ethylene written by Tejaswi Bhavanam and published by . This book was released on 2014 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis and Characterization of Gold Nanoparticles Supported by Polypeptides for Catalytic CO Oxidation written by Scott Kronewitter and published by . This book was released on 2005 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Stable High Temperature Gold Nano catalyst written by Dean Howard Barrett and published by . This book was released on 2012 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heterogeneous Gold Catalysts and Catalysis written by Zhen Ma and published by Royal Society of Chemistry. This book was released on 2014-09-10 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Once considered an inert element, gold has recently gained attention as a catalyst. With hundreds of papers being published each year, this book presents a comprehensive review of this rapidly-evolving field, with contributions by leading experts across the globe. Going through the chapters citing the primary literature, the reader will gain a thorough background to the use of gold in catalysis, as well as the latest methods for the preparation of gold catalysts. Other chapters demonstrate the characterisation and modelling of gold-catalysed reactions, with consideration given to both the fundamentals and commercial applications of this emerging group of catalysts.Written to be accessible by postgraduates and newcomers to the field, this book will also benefit experienced researchers and therefore be an essential reference in the laboratory.
Download or read book Methanol Synthesis Catalyst written by Paul Ben Himelfarb and published by . This book was released on 1983 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmental Catalysis Over Gold based Materials written by George Avgouropoulos and published by Royal Society of Chemistry. This book was released on 2013 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the major developments in hydrogen-related catalytic and electrocatalytic reactions over gold-based materials over the last decade, including many of the advances made by academic and industrial researchers. Gold-based catalysts with potentially exciting new applications in hydrogen technology (e.g. purification of hydrogen, anode/cathode electrodes) are being investigated at a much higher rate than even before. A variety of techniques to synthesize, characterize and evaluate these materials is being employed. The book will be of interest to all those working in catalysis/green chemistry, in particular, to advanced level researchers in catalysis using gold-based materials. It is hoped that specialists in one reaction will read with interest the chapters on the neighbouring expertise. The book is also meant for PhD-students and advanced students interested in this area.
Download or read book Synthesis and Characterization of Gold doped Oxide Catalysts written by Apiwat Rattanachatchai and published by . This book was released on 2000 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gold Nanoparticles Based Novel Solid Catalysts written by Ahmad Alshammari and published by . This book was released on 2010 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Supported Gold Catalysts for Environmental Applications written by Rudie Johan Hendrik Grisel and published by . This book was released on 2002 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nanometal Catalysis in Organic Synthesis written by Ming Bao and published by Springer Nature. This book was released on with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
