An analysis is given of diffusionhyphen;influenced surface reactions using models similar to those used in solution kinetics. It is shown that a pure twohyphen;dimensional model of surface reactions yields no steady state rate constant. By incorporation of adsorption and desorption processes the deficiencies in the twohyphen;dimensional results are eliminated. Expressions are derived for diffusionhyphen;controlled and diffusionhyphen;influenced rate constants for surface reactions. Expressions are also derived for the activation energies of these surface reactions. It is shown that the activation energy for diffusionhyphen;controlled reactions will approximately be given by the activation energy for surface diffusion. Bounding expressions are developed for the activation energy for diffusionhyphen;influenced reactions. Comparisons are made betweeen Langmuirndash;Hinshelwood and Eleyndash;Rideal mechanisms, and it is found that Langmuirndash;Hinshelwood mechanisms should be more important than Eleyndash;Rideal processes for many surface reactions.
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