Atomically-Precise Methods for Synthesis of Solid Catalysts (RSC Catalysis, 22, Band 22) - Hardcover

Hardcover

ISBN 10: 1849738297 ISBN 13: 9781849738293

Verlag: Royal Society of Chemistry, 2014

Inhaltsangabe

There is much interest in preparing catalysts with specific structures for a desired catalytic activity. Although there has been a great amount of research into correlating particles sizes and microstructure to catalytic activity, knowledge about practical catalysts still remain ill-defined. The current challenge is now to understand atomic control.

Atomically-Precise Methods for Synthesis of Solid Catalysts provides an overview of recent developments in heterogeneous catalysts preparation which aim at controlling the microstructure of such catalysts at the atomic scale. Each chapter provides a different synthetic approach to achieve atomic-scale control along techniques to characterize the atomically-precise solids. Topics covered include bimetallic supported catalysts from single-source precursors zeolite-supported molecular metal complex catalyst, surface organometallic chemistry, atomic layer deposition and electron microscopy of catalysts.

Edited by active researchers in the area, the book aims to bridge the gap between surface science and heterogeneous catalysis. The book is suitable for graduate students as well as researchers in academia in industry from various disciplines including engineering, inorganic/organometallic chemistry, surface science and physical chemistry interested in catalyst design.

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Solid catalysts are synthesized to reach the best combination of activity, durability and selectivity. In most chemical systems, these features are intimately correlated with the structure of the active sites, where catalytic conversion proceeds. Although there has been a great amount of research into correlating particles sizes and microstructure to catalytic activity, knowledge about practical catalysts still remain limited. The current challenge is now to attain atomic control.

Atomically-Precise Methods for Synthesis of Solid Catalysts provides an overview of recent developments in heterogeneous catalysts preparation which aim at controlling the microstructure of such catalysts at the atomic scale. Each chapter provides a different synthetic approach to achieve atomic-scale control along techniques to characterize the atomically-precise solids. Topics covered include bimetallic supported catalysts from single-source precursors zeolite-supported molecular metal complex catalyst, atomically-precise nanoparticles, atomic layer deposition and atom probe microscopy, among others.

Edited by active researchers in the area, the book aims to bridge the gap between surface science and heterogeneous catalysis. The book is suitable for graduate students as well as researchers in academia in industry from various disciplines including engineering, inorganic/organometallic chemistry, surface science and physical chemistry, interested in catalyst design.

Aus dem Klappentext

Solid catalysts are synthesized to reach the best combination of activity, durability and selectivity. In most chemical systems, these features are intimately correlated with the structure of the active sites, where catalytic conversion proceeds. Although there has been a great amount of research into correlating particles sizes and microstructure to catalytic activity, knowledge about practical catalysts still remain limited. The current challenge is now to attain atomic control.

Atomically-Precise Methods for Synthesis of Solid Catalysts provides an overview of recent developments in heterogeneous catalysts preparation which aim at controlling the microstructure of such catalysts at the atomic scale. Each chapter provides a different synthetic approach to achieve atomic-scale control along techniques to characterize the atomically-precise solids. Topics covered include bimetallic supported catalysts from single-source precursors zeolite-supported molecular metal complex catalyst, atomically-precise nanoparticles, atomic layer deposition and atom probe microscopy, among others.

Edited by active researchers in the area, the book aims to bridge the gap between surface science and heterogeneous catalysis. The book is suitable for graduate students as well as researchers in academia in industry from various disciplines including engineering, inorganic/organometallic chemistry, surface science and physical chemistry, interested in catalyst design.

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Atomically-Precise Methods for Synthesis of Solid Catalysts

By Sophie Hermans, Thierry Visart de Bocarmé

The Royal Society of Chemistry

Copyright © 2015 The Royal Society of Chemistry
All rights reserved.

ISBN: 978-1-84973-829-3

Contents

Chapter 1 Synthesis of Well-defined Solid Catalysts by Surface Organometallic Chemistry Frédéric Lefebvre, 1, 
Chapter 2 Zeolite-supported Molecular Metal Complex Catalysts Isao Ogino, 27, 
Chapter 3 Bimetallic Supported Catalysts from Single-source Precursors Sophie Hermans, 55, 
Chapter 4 Atomically Precise Gold Catalysis Katla Sai Krishna, Jing Liu, Pilarisetty Tarakeshwar, Vladimiro Mujica, James J. Spivey and Challa S. S. R. Kumar, 87, 
Chapter 5 Atomically Precise Gold Nanoclusters: Synthesis and Catalytic Application Gao Li and Rongchao Jin, 123, 
Chapter 6 Electrochemical Atomic-level Controlled Syntheses of Electrocatalysts for the Oxygen Reduction Reaction Stoyan Bliznakov, Miomir Vukmirovic and Radoslav Adzic, 144, 
Chapter 7 Atomic Layer Deposition in Nanoporous Catalyst Materials Jolien Dendooven, 167, 
Chapter 8 Preparation and Characterization of Model Catalysts for the HCl Oxidation Reaction Christian Kanzler, Herbert Over, Bernd M. Smarsly and Claas Wessel, 198, 
Chapter 9 Controllable Synthesis of Metal Nanoparticles for Electrocatalytic Activity Enhancement Qing Li, Wenlei Zhu and Shouheng Sun, 225, 
Chapter 10 Investigating Nano-structured Catalysts at the Atomic scale by Field Ion Microscopy and Atom Probe Tomography Cédric Barroo, Paul A. J. Bagot, George D. W. Smith and Thierry Visart de Bocarmé, 248, 
Subject Index, 296, 

CHAPTER 1

Synthesis of Well-defined Solid Catalysts by Surface Organometallic Chemistry

FRÉDÉRIC LEFEBVRE

Université Lyon 1, CPE Lyon, CNRS, UMR C2P2, LCOMS, Båtiment CPE Curien, 43 Boulevard du 11 Novembre 1918, F-69616 Villeurbanne, France

Email: lefebvre@cpe.fr

1.1 Introduction

The knowledge in homogeneous catalysis is very high, due to the conceptual advance of molecular organometallic chemistry. Typically, reports in homogeneous catalysis provide not only information on the catalytic performances (activity, selectivity and life time), but also, in most cases, a detailed mechanistic understanding of the catalytic system. The actual elementary steps of the reaction, directly derived from the principles and the investigations of organometallic chemistry, are usually described. This knowledge allows a predictive approach of these systems, mainly based on the fact that it is possible to have only one well-defined catalytic species in the system. Unfortunately, from an industrial point of view, homogeneous catalysis suffers from many disadvantages and very often heterogeneous systems are preferred even if they are ill-defined and less active. The development of better catalysts in heterogeneous catalysis has always relied on empirical considerations since it is difficult to characterize the really active sites on the surfaces, as the so-called 'active sites' are usually in small number(s). At the present time, the number of accepted 'elementary steps' is still limited to a few examples mostly demonstrated by means of surface science, and the predictive approach, based on molecular concepts, is rare. The concept of surface organometallic chemistry has been developed as a possible answer to this problem. Its main objective is the creation on a support (which can be an oxide, a clay, a polymer etc.), of organometallic fragments which will be well-defined and uniform along the entire surface. These species will be characterized by all available physico-chemical methods in order to have a description of the coordination sphere around the metal as precise as possible, as for homogeneous complexes. This strategy, initially proposed by the group of J. M. Basset, has also been developed by other groups (see Table 1.1 for some examples) and has been the subject of numerous reviews and books. In most cases the support was silica (flame silica, porous silica or mesoporous silica) but there are some examples using other oxides such as alumina or magnesia (Table 1.1).

The grafted organometallic complexes can then be modified by using the classical rules of organometallic chemistry leading to species which are potentially active in catalysis. In these compounds the support can be a mono-, di- or tripodal ligand. Recently, a new dimension was added to this chemistry by performing, prior the reaction with the organometallic complex, a reaction replacing the grafting sites by other species such as N–H, Si–H, or phenol groups.

As a consequence, it is now possible to prepare, on a surface, many organometallic complexes where the electronic and steric effects can be tuned easily. This knowledge now allows researchers to have a relatively predictive approach where the starting point is not the organometallic complex but a catalytic reaction. First, a catalytic cycle is proposed on the basis of the classical rules of organometallic chemistry. Second, a grafted organometallic complex which is one species involved in the postulated catalytic cycle is prepared. Third, the catalytic reaction is performed. Depending on the results the ligands around the metal are modified or, if the reaction does not proceed by the proposed catalytic cycle, another mechanism has to be proposed and tested.

We will describe here this surface chemistry via some examples mostly from work done in our laboratory. Our purpose will be to give the rules which will govern the reactivity of the organometallic complexes with the surface and not to compile a complete list of what can be made. We will first describe the grafting sites on the surface as this point will govern the reactivity of organometallic compounds. We will then describe the reaction of these sites with organometallic complexes and how the resulting species can be transformed into active sites before giving some examples in catalysis.

1.2 Grafting Sites of the Support

Organometallic complexes can be deposited on many supports, such as metals, zeolites, oxides or carbons. Depending on the nature, density and homogeneity of the reactive sites on the surface of these materials, different behaviors will be observed, leading to sometimes completely different catalytic applications. As an example we will describe in more detail silica, as it will be extensively used in the following, as it is the simplest support (see Table 1.2 for a non-exhaustive list of grafting sites on other supports). Silica can be considered as the simplest support as it contains only SiO4 tetrahedra linked by [equivalent to]Si–O–Si[equivalent to] bridges. It can be found in various forms such as silica gel, flame silica or mesoporous silica (like MCM-41 or SBA-15). In all cases, at room temperature, the surface is covered by hydroxyl groups [equivalent to]Si–OH and siloxane bridges [equivalent to]Si–O–Si[equivalent to] in interaction with adsorbed water molecules. Upon heating under vacuum at ca. 150 [degrees]C all water molecules are desorbed and the infrared spectrum shows mainly, in the v(O–H) domain, a very broad band between 3700 and 3500 cm-1 attributed to [equivalent to]Si–OH groups linked via hydrogen bonds. Upon heating at higher temperature, condensation between two neighboring hydroxyl groups occurs, leading to the evolution of water molecules and formation of [equivalent to]Si–O–Si[equivalent to] bridges. As a...

Details zur Ausgabe

• Verlag: Royal Society of Chemistry
• Erscheinungsdatum: 2014
• Sprache: Englisch
• ISBN 10: 1849738297
• ISBN 13: 9781849738293
• Einband: Gebundene Ausgabe
• Anzahl der Seiten: 304
• Herausgeber: Hermans Sophie, De Bocarme Thierry Visart, Spivey James J.
• Kontakt zum Hersteller: Nicht verfügbar
• Verantwortliche Person: preigu; mail@preigu.de; ; Lengericher Landstr. 19; Osnabrück; 49078; Deutschland