Hermann Dietz

Gas-diffusion-controlled solid-electrolyte oxygen sensors

The solid-state electrochemical cell O2,Pt/ZrO2(Y2O3)/Pt,O2 was provided with a diffusion barrier of a porous material on the cathode side. On polarisation, limiting currents could be measured which depended linearly on the oxygen concentration. The type of diffusion in the applied diffusion barrier determined the pressure and temperature dependence of such cells. Diffusion barriers with pure bulk diffusion and such with Knudsen diffusion could be prepared. The application of bulk diffusion was advantageous. The stationary oxygen-limiting current is in this case independent of the total pressure and depends only on the mole fraction.