The influence of the oxidic boundary layer on the electrode potential behaviour of gold electrodes with the solid electrolyte Zr0.86Y0.14O1.93 (YSZ) at temperatures less than or equal to 700 degrees C in gases containing oxygen and combustible components was investigated. The interface between gold and the solid electrolyte was chemically modified with TiO2 which was produced in two states (as a surface coating and dissolved in the YSZ boundary layers) after annealing. This was proved by X-ray diffraction with various incidence angles. In the oxygen excess region, the sensitivity to oxidizable gases increases by TiO2-containing interlayers compared to that of the pure Au/YSZ electrode.