Electronic reaction mechanisms

Several very popular and successful interpretations of electronic reaction mechanisms employ orbital models, for example, the Woodward-Hoffmann rules, Fukui s frontier orbital theory, " the Dewar-Zimmerman treatment. 

The studies into the electrochemical kinetics of solvated electrons were to some extent stimulated by the hypothesis put forward in the second half of 6O s (see Sect. 8) for explaining the role of solvated electrons as intermediate products of electrode reactions, and also by the development made at that time in organic synthesis involving the participation of solvated electrons (see Sect. 9). Undoubtedly, knowledge of the mechanism of electrode generation of solvated electrons is of fundamental importance. Electrochemistry is the chemistry of the electron , Professor A. N. Frumkin once said. In fact, electron reactions at the interface of electronic and ionic conductors are inevitably associated with the electron addition or detachment process. In a solvated electron reaction no heavy particle (atom or molecule) acts as electron acceptor, or donor. In this sense, the electrode reactions of solvated electrons are the most simple electrode processes. Therefore, an insight into the solvated electron reaction mechanism is necessary for electrochemical kinetics as a whole. 

The transfer of only one electron in any elementary electrochemical step is the core idea of the developed approach. Like any other fundamental idea, by no means it is new. As it was said before, it was exploited consistently by Vetter in the 1950s of the twentieth century [34]. He considered the intermediates of successive chain of one-electron steps as surface states that neither leave the electrode to pass into the bulk of electrolyte nor tmdergo any chemical transformations. Based on these premises, the two-electron reaction mechanism... 

The ORR performance of three different PANl-derived catalysts in an alkaline electrolyte is shown in Fig. 8.24 [79]. The best performing catalyst, PANl-Co-C, containing a large number of CogSg particles surrounded by nitrogen-doped graphene sheets, shows the activity and performance stabiUty superior to that of a Pt/C reference catalyst. Oxygen is effectively reduced at that catalyst to OH in a four-electron reaction mechanism. 

The polarographic behavior of the anil observed by Lund does not differ from that described in [31], but he rigorously demonstrated an over-all two-electron reaction mechanism, by isolating the product of controlled-potential electrolysis in neutral and alkaline solutions attempts to carry out electrolysis at the first wave at pH 6.0 were unsuccessful. 

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