This volume in the acclaimed series Modern Aspects of Electrochemistry starts with a dedication to the late Professor Brian Conway who for 50 years helped to guide this series to its current prominence. The remainder of the volume is then devoted to the following topics: PEM fuel cells; the use of graphs in electrochemical reaction newtworks; nanomaterials in Lithium-ion batteries; direct methanolf fuel cells (two chapters); fuel cell catalyst layers. The book is for electrochemists, electrochemical engineers, fuel cell workers and energy generation workers.

This volume analyzes and summarizes recent developments in several key interfacial electrochemical systems in the areas of fuel cell electrocatatalysis, electrosynthesis and electrodeposition. The six Chapters are written by internationally recognized experts in these areas and address both fundamental and practical aspects of several existing or emerging key electrochemical technologies. The Chapter by R. Adzic, N. Marinkovic and M. Vukmirovic provides a lucid and authoritative treatment of the electrochemistry and electrocatalysis of Ruthenium, a key element for the devel- ment of efficient electrodes for polymer electrolyte (PEM) fuel cells. Starting from fundamental surface science studies and interfacial considerations, this up-to-date review by some of the pioneers in this field, provides a deep insight in the complex catalytic-electrocatalytic phenomena occurring at the interfaces of PEM fuel cell electrodes and a comprehensive treatment of recent developments in this extremely important field. Several recent breakthroughs in the design of solid oxide fuel cell (SOFC) anodes and cathodes are described in the Chapter of H. Uchida and M. Watanabe. The authors, who have pioneered several of these developments, provide a lucid presentation d- cribing how careful fundamental investigations of interfacial electrocatalytic anode and cathode phenomena lead to novel electrode compositions and microstructures and to significant practical advances of SOFC anode and cathode stability and enhanced electrocatalysis.

No. 29 offers new insights into the energies of activation of electrode reactions and the interfacial behavior of proteins.

It gives us pleasure in writing the Preface to this volume, in which we tried to bring together a number of stimulating and interesting people discussing physical electrochemistry. The first chapter, by Ashok Vijh, gives a remarkable account of electrochemistry as looked at from a physicist's point of view. Among the revelations of the chapter is that in a recent survey of leading areas in Science, two out of fifteen areas chosen were electrochemical and these two were the only chemical subjects chosen. In Mikhail Vorotyntsev's chapter, one finds a very modern study of the double layer, but tenuously connected with the simpler studies made in the safe harbor of mercury. In the pioneering chapter by Pons et al., one is looking at a cutting edge of electrochemistry at this time-the use of IR spectros copy in modes which allow the first practical determinations of the spectra of adsorbed species at the interface-an area pioneered by Pons himself. In Chapter 4, we have reached photoelectrochemistry once more, but now Tributsch speaks about what has rapidly become the major area of that topic, photoelectrocatalysis. Close to this chapter, and indeed intellectually connected with it, is that by Schmickler and Schultze about electron transfer reac tions at oxide-covered metal electrodes in which theories which are still relatively dubious for metal-solution surfaces are applied to complex systems involving oxides.

This volume contains eight chapters covering a wide range of topics: ultrasonic vibration potentials, impedance measurements, photo electrochemical kinetics, chlorine production, electrochemical behavior of titanium, structural properties of membranes, bioelec troche mistry, and small-particle effects for electrocatalysis. Chapter 1, contributed by Zana and Yeager, discusses the little used but potentially important area of ultrasonic vibration potentials. The authors review the historical literature and the associated theoretical equations. They continue by discussing various aspects of the experimental technique and close with a review of the existing studies. They conclude by noting that vibra tion potentials may be useful for determining the effects of various agents on colloidal suspensions found in such important industries as paper production. Chapter 2 is a review of impedance techniques, written by Macdonald and McKubre. The authors include not only derivations of various impedance functions for electrochemical systems but also particularly useful discussions of instrumental methods. The authors close with an interesting claim: "the distribution of current and potential within a porous battery or fuel-cell electrode and within 'flow-through' electrodes is best analyzed in terms of the frequency dispersion of the impedance." Chapter 3, by Khan and Bockris, is a timely review of photo electrochemical kinetics and related devices. Their work begins by reviewing critically important papers on photoelectrochemical kinetics. They continue by presenting detailed discussions concern ing the conceptual ideas of the semiconductor-solution interface.

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 continues the development of the Modern Aspects series in the electrochemical field. The series is now 18 years old, and it is relevant to note the degree of evolution that electro chemistry has undergone during this time, for it affects the character of the articles chosen. The trend is towards development of inter disciplinary areas of electrochemical science, with full stress upon the many directions of applications of knowledge of electrode processes. The degree of import which should be attached to electro chemical science arises from the changes in technology which must be made during the next few decades. These clearly involve a massive electrification and the gradual elimination of the present fossil fuel economy, for both ecological and economic reasons. Research on the fundamental aspects of the field-slow in development to a standard-must be promulgated, but its justification is the modern provisionofa basis for the needed future electrochemical technology. One vast area of potential application of electrochemical concepts is omitted by the present attitude. It is, of course, the electro biological aspect, perhaps, finally, the largest area of all for fruitful applications. These concepts are reflected in the editors' choice of chapters. Quantum mechanical descriptions of surfaces must be bravely faced. Oscillatory aspects of electrochemical systems are often met in nature and demand attention at a fundamental level. Organic electrochemistry is in an ascending phase. With the electro biological v Preface vi article, we hope to stimulate a beginning of electrodic applications in this area.

This volume of Modern Aspects covers a wide spread of topics presented in an authoritative, informative and instructive manner by some internationally renowned specialists. Professors Politzer and Dr. Murray provide a comprehensive description of the various theoretical treatments of solute-solvent interactions, including ion-solvent interactions. Both continuum and discrete molecular models for the solvent molecules are discussed, including Monte Carlo and molecular dynamics simulations. The advantages and drawbacks of the resulting models and computational approaches are discussed and the impressive progress made in predicting the properties of molecular and ionic solutions is surveyed. The fundamental and applied electrochemistry of the silicon/electrolyte interface is presented in an authoritative review by Dr. Gregory Zhang, with emphasis in the preparation of porous silicon, a material of significant technological interest, via anodic dissolution of monocrystalline Si. The chapter shows eloquently how fundamental electrokinetic principles can be utilized to obtain the desired product morphology. Markov chains theory provides a powerful tool for modeling several important processes in electrochemistry and electrochemical engineering, including electrode kinetics, anodic deposit formation and deposit dissolution processes, electrolyzer and electrochemical reactors performance and even reliability of warning devices and repair of failed cells. The way this can be done using the elegant Markov chains theory is described in lucid manner by Professor Thomas Fahidy in a concise chapter which gives to the reader only the absolutely necessary mathematics and is rich in practical examples.

As the subject of electrochemistry moves into the final quarter of the century, a number of developed areas can be assessed in depth while some new areas provide quantitatively and qualitatively novel data and results. The first chapter, by Kebarle, deals with an example of the latter type of field in which new information of the energetics and equilibria of reactions between ions and solvent molecules is studied in the gas phase and provides interesting basic information for treatments of ions in solution, i.e., ionic solvation. Chapter 2, by Hamann, discusses the behavior of electrolyte solutions under high pressures, a matter of intrinsic interest in relation to ion-solvent interaction and the structural aspects of the properties of ionic solutions, especially in water. This topic is also of current interest with regard to the physical chemistry of the marine environment, especially at great depths. In the article by Bloom and Snook (Chapter 3), models for treatments of molten salt systems are examined quantitatively in relation to the structure of molten ionic liquids and to the statistical mechanical approaches that can be meaningfully made to interpret their properties and electrochemical behavior.

From reviews of previous volumes: 'This volume continues the valuable service that has been rendered by the Modern Aspects series.'-Journal of Electroanalytical Chemistry 'Extremely well referenced and very readable....Maintains the overall high standards of the series.'-Journal of the American Chemical Society