In order to clarify the nature of the oxygen species at the Pt surface in electrochemical cells based on yttria-stabilized zirconia (YSZ), we have attempted to obtain in situ Raman spectra of Pt electrode in the temperature range from 300 to 500 degrees C under controlled atmosphere. The nanocrystalline Pt film, 0.5 mu m in thickness, was prepared by a spray pyrolysis technique. We have demonstrated the possibility of monitoring adsorbed oxygen coming from the gas phase or from polarization through YSZ. Surface Pt-O interaction resulting either from oxygen of the gas phase or oxygen supplied electrochemically showed similar spectral signature corresponding to a broad band located near 545 cm(-1) at 350 degrees C. This broad band was tentatively assigned to the Pt-O stretch mode of atomic oxygen on Pt. (c) 2005 Published by Elsevier B.V.