How to Modify Solid Electrodes for Generating New Interfacial Processes — Another Approach in Electro-Chemical Catalysis

Abstract

The word "catalytic" comes from Ancient Greek and can be translated as "a breaking down". The word "catalysis" was introduced in the first half of the 19 th century by the Swedish Scientist J. J. Berzelius who applied it to the observation that in chemical reactions, the normal barriers can be removed by the help of external reagents. Nowadays, the term "catalysis" remains attached to the petroleum refining science introduced more than half a century ago. It mainly refers to the removal of sulfur and nitrogen from naphthas in order to produce fuel (gasoline, diesels, etc.). Refining reactions are conducted in the presence of catalysts often constituting of metals and metal oxides (mixed metal oxides, MMOs) in order to decrease cracking temperatures and improve selectivity of chemical reactions [1,2].In electro-chemistry, the term catalysis is quite recent and remains mainly linked to an easiness in interfacial reactions. Therefore, for It may then appear that most of the 19 chapters that follow this introduction possess an undeniable character of novelty both in the domain of new catalytic reactions, the chemical and electrochemical modifications of conducting solid surfaces, especially in the field of carbons, precious metals and copper. It is obvious however that some parts of the book could present a superficial or unbelievable aspect since both the ideas and the significant results do not go sufficiently into enough details about the scientific aspect and the possible applications. It could actually be the responsibility of the reader to freely reproduce some results and use some ideas (good or judged as incomplete) presented in this research.Among the well-established electro-catalytic processes, redox catalysis remains an intriguing and powerful method that specifically belongs to organic electro-chemistry. This technique 3 corresponds to the innovative and important progress in the field of indirect electrolyses. The first evidence of the indirect reduction of an alkyl-halide RX by the anion radical of naphthalene was reported by Fry [3] while the wide scope of redox catalysis (kinetics and synthetic applications) was unambiguously disclosed by Lund and co-workers [4-6, 8, 16] in the course of 1970s by using polarographic currents of Koutecky's theory. Meanwhile, other authors were also interested in this form of catalysis [7,9,10]. Based on this indirect process, kinetic and thermodynamic results were successfully achieved by by using the voltammetric technique. Thus, for the first time, thermodynamic data and standard potential values concerning reduction of R • radicals (issued from the cleavage of alkyl and aryl halides, (RX's and ArX's)) were appreciated in this way. Thus, RIs (alkyl iodides) in general and certain RBrs (alkyl bromides) may lead to one-electron scissions at cathodes. Therefore, selective one-electron processes and subsequently produced free radicals were considered to be of high interest also for synthesis and they prompted many authors in the course of last three decades to revi...