L. Basini et al., ELECTROCHEMICAL PROMOTION OF OXYGEN-ATOM BACK-SPILLOVER FROM YTTRIA-STABILIZED ZIRCONIA ONTO A POROUS PLATINUM-ELECTRODE - DETECTION OF SERS SIGNALS, Journal of physical chemistry, 98(42), 1994, pp. 10853-10856
During anodic current operation (I = 0.6 mu A) at 315 degrees C of a O
-2, Pt/ZrO2 (8 mol % Y2O3/Ag, O-2 galvanic cell, we have detected Rama
n scattered photons from the Pt electrode. The corresponding bands hav
e been assigned to the transient formation of Pt-O bonds with an unusu
ally low vibrational frequency. The temporal evolution of the signals,
at a constant value of current intensity, temperature, and oxygen flo
w conditions, has been related to the migration (spillover) of oxygen
species from the solid electrolyte-metal-gaseous oxygen three-phase bo
undary zone onto the porous Pt electrode. These observation give direc
t information about oxygen atom motion which results from the O2- ions
pumping toward the working electrode under conditions in which the no
n-Faradaic electrochemical modification of catalytic activity has been
observed.