A GENERALIZED TREATMENT OF THE DYNAMICS OF THE ADSORPTION OF LANGMUIRIAN SYSTEMS AT STATIONARY OR ROTATING-DISK ELECTRODES

A simple but comprehensive analysis of the behavior to be expected fro m molecules whose Langmuirian adsorption on electrodes is controlled b y both their rate of transfer to the surface and the rate of their tra nsformation from the dissolved to the adsorbed state (and vice-versa) is presented. A 'master equation' relating coverage and time is derive d for cases where the mass transport of the adsorbate to the surface o f the electrode is by linear diffusion (stationary electrode) or by co nvection-diffusion (rotating disk electrode). Five sub-cases are exami ned in which the influence of one (or a combination) of the factors co ntrolling the adsorption is dominant. in each case, an easily computed , dimensionless, integral equation depending on only one parameter is derived. Corresponding calculated values of coverage vs. dimensionless time are presented and their shapes are discussed. A global descripti on of the dynamics of adsorption for Langmuirian systems is thereby ac hieved. (C) 1997 Elsevier Science S.A.