HETEROGENEOUS REDOX CATALYSIS AT HYDRATED OXIDE LAYERS

A theoretical model describing heterogeneous redox catalysis at hydrat ed oxide electrodes is described. It is proposed that the transformati on of the substrate to the product occurs via a Michaelis-Menten mecha nism in the hydrated oxide layer. The effect of concentration polariza tion in the electrolyte is included in the theoretical analysis. Analo gies may be drawn between heterogeneous redox catalysis at oxide surfa ces and treatments describing material transport and electrochemical k inetics at enzyme electrodes. The theoretical model is applied to prev iously published data, describing the electro-oxidation of formate at thermally prepared RuO2 electrodes in alkaline solutions.