Plenary Lecture

Functionalized Nanostructured Silica-Based Materials in Electrochemistry

Professor Alain Walcarius
Laboratoire de Chimie Physique et
Microbiologie pour l'Environnement, UMR 7564
CNRS Nancy Universite 405, rue de Vandoeuvre
F-54600 Villers-les-Nancy, France

Abstract: Nanocomposites made of silica-based organic-inorganic hybrid materials displaying a regular mesoporous structure at the mesoporous level, which can be functionalized with appropriate organic groups, are of particular interest for various applications [1]. They indeed provide a unique environment with high accessibility to numerous active centers located in an ordered and mechanically stable structure. Such nanoreactors have recently appeared to be very promising electrode modifiers [2] as they ensure fast mass transport processes, which are often rate-determining in electrochemistry. The aim of this lecture is to highlight and discuss some recent achievements performed at the confluence of these nanostructured materials and electrochemistry, by focusing mainly on thin-film devices.
Three complementary directions will be considered. The first one relies on the usefulness of electrochemical techniques to get information on mass transport through ordered mesoporous films, with special emphasis on the influence of the mesostructure type and the nature of the redox probe on these processes [3]. The second aspect concerns a feedback of materials science to electroanalysis, by exploiting the attractive and sometimes unique properties of mesoporous (organo)silica films on electrodes to improve their sensitivity in comparison to the non-ordered ones, when applied as voltammetric sensing devices [4]. The third domain is related to the use of electrochemistry to prepare thin films of sol-gel-materials via a novel electrochemically-driven deposition method [5], which implies a local electrochemical tuning of pH at the electrode/solution interface to induce co-condensation of the precursors in a controlled way [6]. Even more interesting is the extension of this approach to the preparation of ordered and oriented mesoporous films with mesopore channels oriented perpendicular to the solid surface [7], which has proven to be very difficult by other ways [8]. The method combines the electrochemically-driven self-assembly of surfactants at solid/liquid interfaces [9] and the above electro-assisted generation process to produce sol-gel films [6], leading to perfect alignment of the nanoporous structures normal to the electrode surface [7]. Both preparation and characterization of the oriented mesoporous thin films will be described [10], as well as their functionalization in order to be applied in the field of electrochemical sensors [11]. Such electrochemical nanotechnology is expected to be useful in many other applications.

Brief Biography of the Speaker:
Alain Walcarius received his Ph.D. from the University of Namur (Belgium) in 1994. After a postdoctoral stay in the Joe Wang group in New Mexico State University, he joined the CNRS (France) as a Research Associate. He is currently Research Director in the Laboratory of Physical Chemistry and Microbiology for the Environment (Nancy, France) where his analytical and electroanalytical chemistry group works in the area of reactions at solid/liquid interfaces. Among his actual research interests is the intersection between the chemistry of silica-based organic-inorganic hybrid materials and electro(analytical) chemistry. He has authored and co-authored about 140 papers in international journals and conference proceedings as well as 8 book chapters upon invitation. He is recipient of the Tajima Prize 2006 of the International Society of Electrochemistry.

WSEAS Unifying the Science