Xy. Xiao et al., In situ FTIR spectroscopic investigations of dissociative adsorption and electrooxidation of glycine at the Pt electrode in alkaline solutions, CHEM J CH U, 21(8), 2000, pp. 1288-1292
The dissociative adsorption and electrooxidation of glycine on Pt electrode
in 0.1 mol/L NaOH solutions were studied using cyclic voltammetry and in s
itu FTIR spectroscopy. The results demonstrated that a strong interaction e
xists between glycine and Pt surface, leading to dissociate easily glycine
on Pt surface at potentials below 0.2 V to form cyanide and carboxylate ion
s, The strongly adsorbed cyanide species on the electrode surface can inhib
it the oxidation of glycine, and are considered as poison species for the r
eaction. The oxidation of glycine at potentials above 0.2 V yielded solutio
n species of cyanate and carboxylate. The cyanide species derived from diss
ociative adsorption of glycine can be isolated on electrodes of smooth Pt a
nd nanometer thin Pt film supported on glassy carbon(nm-Pt/GC), and has bee
n determined by in situ FTIRS as showing a band at around 2 100 cm(-1). The
intensity of IR absorption Land of cyanide on nm-Pt/GC surface is 14 times
larger than that on a smooth Pt surface, and the IR band is in the opposit
e direction to that obtained on Pt surface, confirming the adsorption of cy
anide species and the abnormal IR effects. The IR absorption of cyanate and
carboxylate produced in the oxidation of glycine yields infrared bands at
around 2 169 and 1 390 cm(-1), respectively. The present study revealed the
interaction between glycine and Pt electrode surface, and suggested the ad
sorption modes and oxidation mechanism of glycine on Pt electrode as well.