Surface-enhanced IR absorption spectroscopy in attenuated-total reflection（ATR-SEIRAS） configuration was extended for the first time to a cadmium electrode with the adsorption of pyridine as the model system. The SEIRAS active Cd film electrode was prepared by electrodeposition of Cd mulitlayers onto a underlying Au nanofilm on Si in 0.01 mol/L CdSO 4 +0.1 mol/L KClO 4. The morphology of the as-prepared Cd film exhibits an island structure. In the potential range of -1.2 to -0.8 V（vs. SCE）, only in-plane vibrations belonging to the A1 symmetry were detected whereas those to the B1 symmetry virtually were not, suggesting that pyridine coordinates vertically or at a little angle to the Cd electrode surface via its nitrogen end without edge-tilted rotation of its ring plane. The Py adsorption configuration is closed to that found on a Au electrode, but different from that on a Ni or Pt electrode, which may be assigned to different structures of valence electron shells for the substrate metals.
