Voltammetric studies of electrochemical processes at the interface PtlYSZ between 300 and 600°C

Elecln~chemic~d pn~:es~c~ occun'ing ,*kt fire inlerf~lce platinnmly|lria==~,~l~lbilized zirconia were investigaled by cyclic vol|aml)]¢lry and polentiostalic currenlo~poleatial curves, laken n|lder ~leatly~slate condilions, in different mixtures of oxygen and nitrogen at ~e|nperalures between 3tX) and fi00°C. Point or paste electrt~des were used~ The exchange ctnxenl of |be rate-determining slep of the oxygen rednclion I~comes very small below 500°C. Theretbre, the equilibriuin of the oxygen electrode is no longer established. A layer of chemisorbed oxygen aa~ms is lbrmed anodically on the contact surface of the point electrode, not by the dissociation of O, a~ the thrce.pha~e boundary. The shape of the cyclic voitannmograms is discussed. © 1997 Elsevier Science S,A.