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The Snowdonia Conference on electrified interfaces: “Dynamics and structure at electrified interfaces”, 17–21 july 1995
ELSEVIER
Journal of Electroanalytical
Chemistry
409 (1996)
vii-viii
Preface
The Snowdonia Conference on Electrified Interfaces: “Dynamics and Structure at Electrified Interfaces’ ‘, 17-21 July 1995 The Snowdonia Conference on Electrified Interfaces took place in Coleg Harlech, Wales, UK from 17 to 21 July 1995. This was the most recent meeting of a successful series of conferences following the meetings at Snowmass, Logan, Telavi, Berlin, Bologna, and Asilomar. Its purpose was to provide an environment for the discussion of recent achievements and future trends in the fast evolving area of interfacial electrochemistry. The meeting assembled an audience of over a hundred scientists from all over the world. It has been a tradition in this series that new emerging areas are discussed and the topics chosen for the Harlech meeting included those listed here. (i) Novel interfaces, e.g. liquid/liquid interfaces (ii) Self-assembly and chemisorption (iii) Nanostructured materials and semiconductors (iv) Modelling of interfaces and interfacial dynamics (v) Optical and modem imaging methods structure (vi) Mechanism and kinetics in electrocatalysis The format of the Harlech meeting was similar to that of a Gordon Conference. It consisted of sessions with invited lectures and late hour poster sessions. A comprehensive description and discussion of structural aspects and of the kinetics of ion and electron transfer at molecular liquid Iliquid interfaces was presented. The interest of these systems is the possibility of investigating electrochemical processes in the absence of a solid phase, in which case ion-solvent interactions play a dominant role in determining interfacial organization, structure and reactivity. The new technique of second harmonic generation spectroscopy is ideally suited for these studies, because a centre of symmetry is absent at the interface. Self-assembled structures have attracted very considerable interest in the last decade since the discovery that thiols are chemically attached to gold surfaces to give self-organ&d structures. Simultaneously with these studies, important new developments in studies of organic adsorption in ultrahigh vacuum conditions are yielding a fascinating insight into the nature of self-organization. Synthetic routes have been developed for surface derivatization with organic films of variable barrier properties and reactivity and the mechanism of electron transfer through these ultrathin films has stimulated many electrochemical studies.
Some of the key players in these fields of research gave excellent presentations, not only on structural aspects but also on the dynamics of surface transformations of adsorbed layers. Important contributions showed that two-dimensional transformations, traditionally studied at the mercury 1solution interface, can now be observed at single crystal electrodes. These are very interesting developments; for instance, the advent of fast, ultrastable STM equipment is opening up the possibility of following the dynamics of surface transformations not only by classical electrochemical measurements, but also by direct imaging. This research has implications both in industrially relevant applications such as metal plating and surface finishing and for the physical chemistry of adsorption on well-defined surfaces. Both aspects were discussed during the meeting. The question of surface control has become a central issue of modem electrochemical research and, in this respect, there is a clear indication that the control of the structure of electrocatalytic surfaces requires an understanding of metals of nanometre dimensions. The effect of size on the electronic properties of materials (quantum size effects) has been known for some time. However, the controlled synthesis of nanostructured materials is in its infancy and several papers dealt with some of the recent advances in this field. This was presented as an organic synthesis problem, for the preparation of photoluminescent materials from porous silicon and for their use as electrocatalytic surfaces. There are very rapid advances in the synthetic chemistry of nanostructured materials, and it would be expected that a very large effort in this direction will occur in the next few years due to the exquisite control that modem synthetic methods can bring to bear on the problem of defining surface structures. The theory and modelling of interfaces and interfacial dynamics was extensively discussed during the meeting, for instance in relation to two-dimensional phase transitions and adsorption on single-crystal substrates. The advent of cheap computers is creating a new way of looking at interfacial problems and molecular dynamics calculations are becoming realistic models of behaviour. It is of particular interest that water structural aspects can now be incorporated in models of the double layer.
viii
Prefuce
Optical methods, imaging techniques and other nontraditional electrochemical techniques have been at the core of the development of modem electrochemical science, and recent developments in these areas were extensively discussed at Harlech. Examples of these are the use of FITR for the investigations of electrosynthetic reactions and of structural characteristics, the development of far-infrared techniques for the study of anion adsorption, the ultrafast methods of sum frequency generation using a free electron laser, the use of surface plasmon resonance microscopy to detect the course of oscillatory reactions, the use of surface imaging for semiconductor surface characterization and the exciting possibilities offered by the application of NMR spectroscopy to the chemical characterization of adsorbed intermediates. The combination of electrochemistry and UHV experiments has provided an insight for the understanding of detailed mechanisms of electrocatalytic processes, and the possibilities offered by this powerful approach were extensively discussed during the meeting.
As has been traditional in these meetings, a general discussion session generated a great deal of argumentation. The need was highlighted to capitalize on the rapid development of our understanding of structural aspects of electrified interfaces in the recent past in order to provide a more solid background for processes of potential industrial interest. Harlech provided an excellent background for the meeting, thanks to the scenic beauty of the Welsh coast and mountains, and its isolation. It was agreed that the next meeting will take place in Portugal in 1998 and will be organised by Professor Fernando Silva. There are also plans for future meetings in North-Western Germany to be organized by Ulrich Stimming and in Canada by Jacek Lipkowski.
Richard J. Nichols David J. Schiffrin
Journal of Electroanalytical
Chemistry
409 (1996)
vii-viii
Preface
The Snowdonia Conference on Electrified Interfaces: “Dynamics and Structure at Electrified Interfaces’ ‘, 17-21 July 1995 The Snowdonia Conference on Electrified Interfaces took place in Coleg Harlech, Wales, UK from 17 to 21 July 1995. This was the most recent meeting of a successful series of conferences following the meetings at Snowmass, Logan, Telavi, Berlin, Bologna, and Asilomar. Its purpose was to provide an environment for the discussion of recent achievements and future trends in the fast evolving area of interfacial electrochemistry. The meeting assembled an audience of over a hundred scientists from all over the world. It has been a tradition in this series that new emerging areas are discussed and the topics chosen for the Harlech meeting included those listed here. (i) Novel interfaces, e.g. liquid/liquid interfaces (ii) Self-assembly and chemisorption (iii) Nanostructured materials and semiconductors (iv) Modelling of interfaces and interfacial dynamics (v) Optical and modem imaging methods structure (vi) Mechanism and kinetics in electrocatalysis The format of the Harlech meeting was similar to that of a Gordon Conference. It consisted of sessions with invited lectures and late hour poster sessions. A comprehensive description and discussion of structural aspects and of the kinetics of ion and electron transfer at molecular liquid Iliquid interfaces was presented. The interest of these systems is the possibility of investigating electrochemical processes in the absence of a solid phase, in which case ion-solvent interactions play a dominant role in determining interfacial organization, structure and reactivity. The new technique of second harmonic generation spectroscopy is ideally suited for these studies, because a centre of symmetry is absent at the interface. Self-assembled structures have attracted very considerable interest in the last decade since the discovery that thiols are chemically attached to gold surfaces to give self-organ&d structures. Simultaneously with these studies, important new developments in studies of organic adsorption in ultrahigh vacuum conditions are yielding a fascinating insight into the nature of self-organization. Synthetic routes have been developed for surface derivatization with organic films of variable barrier properties and reactivity and the mechanism of electron transfer through these ultrathin films has stimulated many electrochemical studies.
Some of the key players in these fields of research gave excellent presentations, not only on structural aspects but also on the dynamics of surface transformations of adsorbed layers. Important contributions showed that two-dimensional transformations, traditionally studied at the mercury 1solution interface, can now be observed at single crystal electrodes. These are very interesting developments; for instance, the advent of fast, ultrastable STM equipment is opening up the possibility of following the dynamics of surface transformations not only by classical electrochemical measurements, but also by direct imaging. This research has implications both in industrially relevant applications such as metal plating and surface finishing and for the physical chemistry of adsorption on well-defined surfaces. Both aspects were discussed during the meeting. The question of surface control has become a central issue of modem electrochemical research and, in this respect, there is a clear indication that the control of the structure of electrocatalytic surfaces requires an understanding of metals of nanometre dimensions. The effect of size on the electronic properties of materials (quantum size effects) has been known for some time. However, the controlled synthesis of nanostructured materials is in its infancy and several papers dealt with some of the recent advances in this field. This was presented as an organic synthesis problem, for the preparation of photoluminescent materials from porous silicon and for their use as electrocatalytic surfaces. There are very rapid advances in the synthetic chemistry of nanostructured materials, and it would be expected that a very large effort in this direction will occur in the next few years due to the exquisite control that modem synthetic methods can bring to bear on the problem of defining surface structures. The theory and modelling of interfaces and interfacial dynamics was extensively discussed during the meeting, for instance in relation to two-dimensional phase transitions and adsorption on single-crystal substrates. The advent of cheap computers is creating a new way of looking at interfacial problems and molecular dynamics calculations are becoming realistic models of behaviour. It is of particular interest that water structural aspects can now be incorporated in models of the double layer.
viii
Prefuce
Optical methods, imaging techniques and other nontraditional electrochemical techniques have been at the core of the development of modem electrochemical science, and recent developments in these areas were extensively discussed at Harlech. Examples of these are the use of FITR for the investigations of electrosynthetic reactions and of structural characteristics, the development of far-infrared techniques for the study of anion adsorption, the ultrafast methods of sum frequency generation using a free electron laser, the use of surface plasmon resonance microscopy to detect the course of oscillatory reactions, the use of surface imaging for semiconductor surface characterization and the exciting possibilities offered by the application of NMR spectroscopy to the chemical characterization of adsorbed intermediates. The combination of electrochemistry and UHV experiments has provided an insight for the understanding of detailed mechanisms of electrocatalytic processes, and the possibilities offered by this powerful approach were extensively discussed during the meeting.
As has been traditional in these meetings, a general discussion session generated a great deal of argumentation. The need was highlighted to capitalize on the rapid development of our understanding of structural aspects of electrified interfaces in the recent past in order to provide a more solid background for processes of potential industrial interest. Harlech provided an excellent background for the meeting, thanks to the scenic beauty of the Welsh coast and mountains, and its isolation. It was agreed that the next meeting will take place in Portugal in 1998 and will be organised by Professor Fernando Silva. There are also plans for future meetings in North-Western Germany to be organized by Ulrich Stimming and in Canada by Jacek Lipkowski.
Richard J. Nichols David J. Schiffrin