ADSORPTION OF WATER AT PT(111) ELECTRODE IN HCLO4 SOLUTIONS - THE POTENTIAL OF ZERO CHARGE

摘要

FTIR reflection-absorption spectra at Pt(lll) show potential dependent bands near 3100 and 1620 cm(-1), corresponding respectively to the O-H stretching and H-O-H in-plane deformation of adsorbed water molecules. At around 0.35 V vs. RHE, water orientation changes from hydrogen down to oxygen down indicating that the zero charge potential of Pt(lll) is close to this value. In the potential region corresponding to the anomalous wave of Pt(111) the bending frequency decreases, consistent with a strengthening of the H2O-Pt interaction. A band at 3270 cm(-1) is assigned to adsorbed hydroxyl ions formed by partial dissociation of water. The vibrational behavior is correlated with the features in the voltammogram. [References: 31]