Scope and Significance of this Article

The Tafel equation rj = a b ni, where fc, the so-called Tafel slope, conventionally written in the form b = RT/aF, where a is a charge transfer coefficient, has formed the basis of empirical and theoretical representations of the potential dependence of electrochemical reaction rates, in fact since the time of Tafel s own work. It will be useful to recall here, at the outset, that the conventional representation of the Tafel slope as RT/aF arises in a simple way from the supposition that the free energy of activation AG becomes modified in an electrochemical reaction by some fraction, 0.5, of the applied potential expressed as a relative electrical energy change rjF, and that the resulting combination of AG and 0.5tjF are subject to a Boltzmann distribution in an electrochemical Arrhenius equation involving an exponent n I/RT. Hence we have the conventional role of T in b = RT/aF, as will be discussed in more detail later. 

Despite the almost universal adoption of the form in which b is written above and the implicit assumption therefore that b is proportional to temperature T, there now exists a sufficient number 

This paper examines this whole problem in a comprehensive way and reports some new examples of nonconventional behavior of b with respect to temperature. 

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