NON-FARADAIC ELECTROCHEMICAL MODIFICATION OF CATALYTIC ACTIVITY .5. OXYGEN-CHEMISORPTION ON SILVER

The technique of isothermal surface titration was used to investigate the chemisorptive properties of porous Ag films deposited on Y2O3-doped ZrO2 in a solid electrolyte cell. It was found that the chemisorptive properties of Ag can be influenced in a pronounced and reversible manner upon polarizing electrochemically the metal-solid electrolyte interface. Decreasing catalyst work function has very little effect on subsurface oxygen but strengthens significantly the Ag-atomic oxygen chemisorptive bond, as inferred both by the observed pronounced increases in the rate of oxygen adsorption and in the equilibrium oxygen coverage and by the observed significant decrease in the rate of atomic oxygen desorption. The results are consistent with the previously proposed interpretation of the NEMCA effect and show that solid electrolytes can be used as active catalyst supports to alter significantly the chemisorptive and catalytic properties of metals. © 1992.