The influence of the polarization of the RuO2/YSZ interface on the electrochem. promotion of RuO2 catalysts was studied by temp. programmed desorption and high temp. cyclic voltammetry measurements. The desorption activation energy of adsorbed oxygen decreases from 2.32 eV at 380 mV to 7.26 eV at 600 mV by polarizing of the RuO2/YSZ interface. A higher oxide (RuO3) might be formed at the RuO2/YSZ interface during anodic polarization. [on SciFinder (R)]