Abstract: The dissociative adsorption and electrooxidation of glycine on Pt electrode in 0.1 mol/L NaOHsolutions were studied using cyclic voltammetry and in situ FTIRspectroscopy. The results demonstrated that a strong interaction exists between glycine and Pt surface, leading to dissociate easily glycine on Pt surface at potentials below 0.2 Vto form cyanide and carboxylate ions. The strongly adsorbed cyanide species on the electrode surface can inhibit the oxidation of glycine, and are considered as poison species for the reaction. The oxidation of glycine at potentials above 0.2 Vyielded solution species of cyanate and carboxylate. The cyanide species derived from dissociative adsorption of glycine can be isolated on electrodes of smooth Pt and nanometer thin Pt film supported on glassy carbon(nm-Pt/GC), and has been determined by in situ FTIRSas showing a band at around 2100 cm^-1 . The intensity of IRabsorption band of cyanide on nm-Pt/GCsurface is 14 times larger than that on a smooth Pt surface, and the IRband is in the opposite direction to that obtained on Pt surface, confirming the adsorption of cyanide species and the abnormal IReffects. The IRabsorption of cyanate and carboxylate produced in the oxidation of glycine yields infrared bands at around 2169 and 1390 cm^-1 , respectively. The present study revealed the interaction between glycine and Pt electrode surface, and suggested the adsorption modes and oxidation mechanism of glycine on Pt electrode as well.

Key words: Glycine, Dissociative adsorption, Electrooxidation, Pt electrode, In situ FTIR spectra