Costas G. Vayenas – författare

I knew nothing of the work of C. G. Vayenas on NEMCA until the early nineties. Then I learned from a paper of his idea (gas interface reactions could be catalyzed electrochemically), which seemed quite marvelous; but I did not understand how it worked. Consequently, I decided to correspond with Professor Vayenas in Patras, Greece, to reach a better understanding of this concept. I think that my early papers (1946, 1947, and 1957), on the relationship between the work function of metal surfaces and electron transfer reactions thereat to particles in solution, held me in good stead to be receptive to what Vayenas told me. As the electrode potential changes, so of course, does the work function at the interface, and gas metal reactions there involve adsorbed particles which have bonding to the surface. Whether electron transfer is complete in such a case, or whether the effect is on the desorption of radicals, the work function determines the strength of their bonding, and if one varies the work function by varying the electrode potential, one can vary the reaction rate at the interface. I got the idea. After that, it has been smooth sailing. Dr. Vayenas wrote a seminal article in Modern Aspects of Electrochemistry, Number 29, and brought the field into the public eye. It has since grown and its usefulness in chemical catalytic reactions has been demonstrated and verified worldwide.

This text explores several aspects of electrochemistry. It includes a chapter on electrochemical nuclear magnetic resonance (EC-NMR) - a powerful non-invasive technique which brings insights to both fundamental and practical key aspects of electrocatalysis, including the design of better anodes for PEM fuel cells. There is also a chapter devoted to advances in the use of rigorous ab initio quantum chemical calculations in electrochemistry, addressed to all electrochemists, including those with very little prior exposure to quantum chemistry, and demonstrates the usefulness of ab initio calculations, including density functional theory (DFT) methods, to understand several key aspects of fuel cell electrocatalysis at the molecular level.The text also discusses the most important macroscopic and statistical thermodynamic models developed to describe adsorption phenomena on electrodes, including the state of the art adsorption isotherms, which are both rigorous, and in good agreement with experiment, as well as electrochemical promotion - the use of electrochemistry to activate and in situ tune the catalytic activity and selectivity of metal and metal oxide catalysts interfaced with solid electrolytes.

I knew nothing of the work of C. G. Vayenas on NEMCA until the early nineties. Then I learned from a paper of his idea (gas interface reactions could be catalyzed electrochemically), which seemed quite marvelous; but I did not understand how it worked. Consequently, I decided to correspond with Professor Vayenas in Patras, Greece, to reach a better understanding of this concept. I think that my early papers (1946, 1947, and 1957), on the relationship between the work function of metal surfaces and electron transfer reactions thereat to particles in solution, held me in good stead to be receptive to what Vayenas told me. As the electrode potential changes, so of course, does the work function at the interface, and gas metal reactions there involve adsorbed particles which have bonding to the surface. Whether electron transfer is complete in such a case, or whether the effect is on the desorption of radicals, the work function determines the strength of their bonding, and if one varies the work function by varying the electrode potential, one can vary the reaction rate at the interface. I got the idea. After that, it has been smooth sailing. Dr. Vayenas wrote a seminal article in Modern Aspects of Electrochemistry, Number 29, and brought the field into the public eye. It has since grown and its usefulness in chemical catalytic reactions has been demonstrated and verified worldwide.

This volume of Modern Aspects contains a remarkable spread of topics covered in an authoritative manner by some internationally renowned specialists. In a seminal chapter Drs. Babu, Oldfield and Wieckowski demonstrate eloquently the strength of electrochemical nuclear magnetic resonance (EC-NMR) to study in situ both sides of the electrochemical interface via the simultaneous use of and This powerful non-invasive technique brings new insights to both fundamental and practical key aspects of electrocatalysis, including the design of better anodes for PEM fuel cells. The recent impressive advances in the use of rigorous ab initio quantum chemical calculations in electrochemistry are described in a remarkable chapter by Marc Koper, one of the leading protagonists in this fascinating area. This lucid chapter is addressed to all electrochemists, including those with very little prior exposure to quantum chemistry, and demonstrates the usefulness of ab initio calculations, including density functional theory (DFT) methods, to understand several key aspects of fuel cell electrocatalysis at the molecular level. The most important macroscopic and statistical thermodynamic models developed to describe adsorption phenomena on electrodes are presented critically in a concise and authoritative chapter by Panos Nikitas. The reader is guided through the seminal contributions of Frumkin, Butler, Bockris, Guidelli and others, to the current state of the art adsorption isotherms, which are both rigorous, and in good agreement with experiment.

Topics discussed include: Solid State Electrochemistry, Kinetics of Electrochemical Hydrogen Entry into Metals and Alloys, Electrochemistry of Titanium, Electrochemical Oxidation of Organics on Synthetic Diamond-based Electrodes, Fuel Cells, Trace-Anion Catalysis of Outer-Sphere Heterogeneous Charge-Transfer Reactions, Thermodynamic and Transport Properties of Bridging Electrolyte - Water Systems Hydrogen, diamond electrodes, and fuel cells were all topics of intense interest at the 2003 ECS meeting in Paris.

This volume of Modern Aspects contains a remarkable spread of topics covered in an authoritative manner by some internationally renowned specialists. In a seminal chapter Drs. Babu, Oldfield and Wieckowski demonstrate eloquently the strength of electrochemical nuclear magnetic resonance (EC-NMR) to study in situ both sides of the electrochemical interface via the simultaneous use of and This powerful non-invasive technique brings new insights to both fundamental and practical key aspects of electrocatalysis, including the design of better anodes for PEM fuel cells. The recent impressive advances in the use of rigorous ab initio quantum chemical calculations in electrochemistry are described in a remarkable chapter by Marc Koper, one of the leading protagonists in this fascinating area. This lucid chapter is addressed to all electrochemists, including those with very little prior exposure to quantum chemistry, and demonstrates the usefulness of ab initio calculations, including density functional theory (DFT) methods, to understand several key aspects of fuel cell electrocatalysis at the molecular level. The most important macroscopic and statistical thermodynamic models developed to describe adsorption phenomena on electrodes are presented critically in a concise and authoritative chapter by Panos Nikitas. The reader is guided through the seminal contributions of Frumkin, Butler, Bockris, Guidelli and others, to the current state of the art adsorption isotherms, which are both rigorous, and in good agreement with experiment.

This volume of Modern Aspects contains seven chapters. The major topics covered in the first six chapters of this volume include fundamentals of solid state electrochemistry; kinetics of electrochemical hydrogen entry into metals and alloys; oxidation of organics; fuel cells; electrode kinetics of trace-anion catalysis; nano structural analysis. The last chapter is a corrected version of chapter four from Volume 35. Faisal M. AI-faqeer and Howard W. Pickering begin the first chapter by going back to 1864 and Cailletet who found that some hydrogen evolved and was absorbed by iron when it was immersed in dilute sulfuric acid. The absorption of hydrogen into metals and alloys can lead to catastrophic failures of structures. They discuss the kinetics of electrochemical hydrogen entry into metals and alloys. In chapter three, Clyde L. Briant reviews the electrochemistry, corrosion and hydrogen embrittlement of unalloyed titanium. He begins by reviewing the basic electrochemistry and general corrosion of titanium. He also discusses pitting and galvanostatic corrosion followed by a review of hydrogen embrittlement emphasizing the formation of hydrides and the effect of these on titanium''s mechanical properties. Christos Comninellis and Gy6rgy F6ti discuss the oxidative electrochemical processes of organics in chapter three. They begin by defining direct and indirect electrochemical oxidation of organics. They introduce a model that allows them to distinguish between active (strong) and non-active (weak) anodes. Different classes of organic compounds are used for kinetic models of organic oxidation at active and non-active type anodes.

This volume of Modern Aspects contains seven chapters. The major topics covered in the first six chapters of this volume include fundamentals of solid state electrochemistry; kinetics of electrochemical hydrogen entry into metals and alloys; oxidation of organics; fuel cells; electrode kinetics of trace-anion catalysis; nano structural analysis. The last chapter is a corrected version of chapter four from Volume 35. Faisal M. AI-faqeer and Howard W. Pickering begin the first chapter by going back to 1864 and Cailletet who found that some hydrogen evolved and was absorbed by iron when it was immersed in dilute sulfuric acid. The absorption of hydrogen into metals and alloys can lead to catastrophic failures of structures. They discuss the kinetics of electrochemical hydrogen entry into metals and alloys. In chapter three, Clyde L. Briant reviews the electrochemistry, corrosion and hydrogen embrittlement of unalloyed titanium. He begins by reviewing the basic electrochemistry and general corrosion of titanium. He also discusses pitting and galvanostatic corrosion followed by a review of hydrogen embrittlement emphasizing the formation of hydrides and the effect of these on titanium's mechanical properties. Christos Comninellis and Gy6rgy F6ti discuss the oxidative electrochemical processes of organics in chapter three. They begin by defining direct and indirect electrochemical oxidation of organics. They introduce a model that allows them to distinguish between active (strong) and non-active (weak) anodes. Different classes of organic compounds are used for kinetic models of organic oxidation at active and non-active type anodes.