Electrochemical behaviour of amino acids on Pt(h,k,l): a voltammetric and in situ FTIR study. Part 1. Glycine on Pt(111)

Abstract

A spectroelectrochemical study of the adsorption and oxidation of glycine on a Pt(111) electrode has been carried out in 0.1 M HClO4 solution. Two types of adsorbate were identified. On the one hand, strongly adsorbed cyanide which comes from the oxidative adsorption of the molecule. This adsorbate has been isolated and characterized. On the other hand reversibly adsorbed glycinate anions, which adsorb at potentials above 0.3 V, have been detected. As in the case of acetate anions, glycinate is two-fold coordinated to the Pt(111) surface through the carboxylate group. The analysis of the potential dependent band centre frequencies and integrated band intensities suggests that lateral interactions between adsorbed glycinate anions are at the origin of the small frequency shift observed with increasing potential.