CATALYSIS OF REACTIONS INVOLVING OXIDES OF CARBON AND NITROGEN BY THE FERROELECTRIC COMPOUND POTASSIUM NIOBATE

The adsorption of nitric oxide (NO) and the catalysis of several chemical reactions involving oxides of carbon and nitrogen have been investigated over the ferroelectric compound potassium niobate (KNbO3). Auger electron spectroscopy measurements reveal selective adsorption of NO on ferroelectric domains of KNbO3 with a particular orientation of electric polarization. Linearly programmed thermal desorption measurements indicate that the NO molecules desorb from two different types of surface sites with activation energies of 7 ± 1 kcal/mole and 45 ± 6 kcal/mole. The rates of the reactions involving oxides of carbon and nitrogen, measured by means of a microcatalytic technique, did not exhibit any anomalies in the vicinity of the Curie temperature of KNbO3. This suggests that the order parameter characterizing the ferroelectric phase transition in KNbO3 is only weakly coupled to the reactant degrees of freedom for the reactions that were investigated. © 1979.