ELECTROCHEMICAL-BEHAVIOR OF AMINO-ACIDS ON PT(H,K,L) - A VOLTAMMETRICAND IN-SITU FTIR STUDY .1. GLYCINE ON PT(111)

A spectroelectrochemical study of the adsorption and oxidation of glyc ine on a Pt(111) electrode has been carried out in 0.1 M HClO4 solutio n. Two types of adsorbate were identified. On the one hand, strongly a dsorbed cyanide which comes from the oxidative adsorption of the molec ule. This adsorbate has been isolated and characterized. On the other hand reversibly adsorbed glycinate anions, which adsorb al potentials above 0.3 V, have been detected. As in the case of acetate anions, gly cinate is two-fold coordinated to the Pt(111) surface through the carb oxylate group. The analysis of the potential dependent band centre fre quencies and integrated band intensities suggests that lateral interac tions between adsorbed glycinate anions are at the origin of the small frequency shift observed with increasing potential.