The electrochem. promotion of the complete catalytic oxidn. of ethylene and toluene on RuO2Catalyst films deposited on Y2O3-stabilized-ZrO2 (YSZ) was studied at temps. 400 to 500 Deg. Anodic polarization (1.5 V), i.e. O2- supply from the YSZ support to the catalyst, is found to enhance the rates of ethylene and toluene oxidn. by a factor of 10 and 8 resp. Cathodic polarization (-1.5 V) i.e. oxygen removal from the catalyst, enhances the oxidn. rates by a factor of 3 and 4, resp. These rate enhancements are strongly nonfaradaic. The kinetics, pos. order in both reactants, and the promotional results, inverted-volcano type for both reactions, conform to the recently found rules of electrochem. promotion. [on SciFinder (R)]