Electrocatalysis overview

In the first part of the present review, new techniques of preparation of modified electrodes and their electrochemical properties are presented. The second part is devoted to applications based on electrochemical reactions of solute species at modified electrodes. Special focus is given to the general requirements for the use of modified electrodes in synthetic and analytical organic electrochemistry. The subject has been reviewed several times Besides the latest general review by Murray a number of more recent overview articles have specialized on certain aspects macro-molecular electronics theoretical aspects of electrocatalysis organic applicationssensor electrodes and applications in biological and medicinal chemistry. 

The aim of this overview is first to present the general principles of electrocatalysis by metal complexes, followed by a series of selected examples published over the last 20 years illustrating the major electrochemical reactions catalyzed by metal complexes and their potential applications in synthetic and biomimetic processes, and also in the development of sensory devices. The area of metal complex catalysts in electrochemical reactions was reviewed in 1990.1... 

The book is divided into six parts theory of nanoparticle catalysis and electrocatalysis model systems from single crystals to nanoparticles synthetic approaches in nanoparticle catalysis and electrocatalysis advanced experimental concepts particle size, support, and promotional effects and advanced electro-catalytic materials. This facilitates access to the general reader s interests. Each chapter begins with a summary and a table of contents to provide an overview of its scope. 

The next section gives a brief overview of the main computational techniques currently applied to catalytic problems. These techniques include ab initio electronic structure calculations, (ab initio) molecular dynamics, and Monte Carlo methods. The next three sections are devoted to particular applications of these techniques to catalytic and electrocatalytic issues. We focus on the interaction of CO and hydrogen with metal and alloy surfaces, both from quantum-chemical and statistical-mechanical points of view, as these processes play an important role in fuel-cell catalysis. We also demonstrate the role of the solvent in electrocatalytic bondbreaking reactions, using molecular dynamics simulations as well as extensive electronic structure and ab initio molecular dynamics calculations. Monte Carlo simulations illustrate the importance of lateral interactions, mixing, and surface diffusion in obtaining a correct kinetic description of catalytic processes. Finally, we summarize the main conclusions and give an outlook of the role of computational chemistry in catalysis and electrocatalysis. 

Carbon supported Pt and Pt-alloy electrocatalysts form the cornerstone of the current state-of-the-art electrocatalysts for medium and low temperature fuel cells such as phosphoric and proton exchange membrane fuel cells (PEMECs). Electrocatalysis on these nanophase clusters are very different from bulk materials due to unique short-range atomic order and the electronic environment of these cluster interfaces. Studies of these fundamental properties, especially in the context of alloy formation and particle size are, therefore, of great interest. This chapter provides an overview of the structure and electronic nature of these supported... 

Investigation of carbon dioxide catalytic activation is explored by a variety of subdisciplines (homogeneous catalysis, heterogeneous catalysis, electrocatalysis/photoelectrocatalysis), often with little cross-citation of work. This situation created a need to bring together the leading researchers to provide an overview of methods and accomplishments to date. 

The rare-earth-containing mixed oxides commonly used in catalytic applications will be presented in the first section of this chapter. In the second section, the applications to different types of reactions will be described, making cross-references among them. The final section will provide a general overview of other miscellaneous applications connected to their catalytic properties such as photocatalysis, electrocatalysis and gas sensors. 

Metallic-particle-based CP nanocomposites arc explored in view of a great variety of applications, including electrocatalysis, electroanalytics, soisorics, corrositm protection etc. The discussion in this chapter concerning apphcati( is will address the relationship between synthetic conditions and mainly electrocatalytic and electroanalytic performance, without going into the specifie topic of mechanisms of electrochemical reactitMis. The latter research area (see e.g. [9]) requires extensive presentation and remains outside the seope of this overview. 

The overview presented so far has shown the manifold activities of synthetic chemists and electrochemists to produce various metallic-based CP nanocomposite materials. These efforts have been directed to a diversity of applications, e.g. electrocatalysis, electroanalytics, chemical and electrochemical sensing etc. To outline these areas of research is a separate task that remains outside the scope of this chapter. Nevertheless, for the prevailing niunber of investigations, where the synthetic work has been combined with applications-related measurements, a brief outline will be presented here. 

An Overview of the Application of Nitrides and Oxynitrides in Photocatalysis and Electrocatalysis... 

Nitrides have also been studied within the domain of electrocatalysis are materials that accelerate the rate of electrochemical reactions on an electrode surface. Although out of the scope of this overview, studies into the use of carbonitrides and carbon-supported nitrides have found some interest in the electrocatalytic literature as detailed in a number of publications [59 - 62]. This section is intended to... 

This brief overview has detailed the interest in the application of nitrides and oxynitrides as photocatalysts and electrocatalysts with some emphasis on the role of preparation. In both applications, they represent classes of materials, which form part of a wider research effort. Band gap energies of nitrides and oxynitrides, as a function of composition, have been the primary interest for photocatalytic applications, whereas the potential of nitrides as replacements for precious metals is the main direction in electrocatalysis. In any large-scale application, convenient and reproducible preparation routes will be important - these are aspects, which have not been particularly well addressed in the literature to date, although the identification of large-scale applications would no doubt spur activity in this area. 

Chapters 7-12 focus on the electrocatalysis of carbon-based non-precious metal catalysts. The unique properties and fuel cell applications of various carbon based catalysts are intensively discussed in these chapters. Chapter 7 summarizes the fundamental studies on the electrocatalytic properties of metallomacrocyclic and other non-macrocyclic complexes. Chapter 8 and 9 review the progress made in the past 5 years of pyrolyzed carbon-supported nitrogen-coordinated transition metal complexes. Chapter 10 gives a comprehensive discussion on the role of transitional metals in the ORR electrocatalysts in acidic medium. Chapter 11 introduces modeling tools such as density functional theory (DPT) and ah initio molecular dynamics (AIMD) simulation for chemical reaction studies. It also presents a theoretical point of view of the ORR mechanisms on Pt-based catalysts, non-Pt metal catalysts, and non-precious metal catalysts. Chapter 12 presents an overview on recent progresses in the development of carbon-based metal-free ORR electrocatalysts, as well as the correlation between catalyst structure and their activities. 

Overview of the Roles of Adsorbates During Electrocatalysis in RTILs... 

In a recent review paper by Shao (2011) the author mentions that because of limited resources and high cost, platinum electrocatalysts, used in many low-temperature fuel cells, hinder the commercialization of fuel cell power plants. Recent efforts have focused on the discovery of palladium-based electrocatalysts with no or little platinum. The paper overviews progress in electrocatalysis by palladium-based materials for the reaction of hydrogen oxidation as well for the reaction of oxygen reduction (see the next section). 

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