in situ FTIR Spectroscopic Studies of Adsorption and Oxidation of L-Serine on Pt Electrodes in Neutral Solutions

The dissociative adsorption and oxidation of L-serine on platinum electrode in neutral solutions were studied via in situ FTIR reflection spectroscopy and electrochemical methods.The FTIRS results demonstrate that the serine can be easily dissociated on Pt surface at potentials below-0.6 V(vs.SCE) to form cyanide(~2100 cm-1) and carbon monoxide(COL,~2034 cm-1;COB,~1870 cm-1).The observation of an absorption band at 2343 cm-1 is ascribed to CO2,which implies the cleavage of the C—C bond during the dissociative adsorption of serine.It has determined that the cyanide was strongly adsorbed on electrode surface in a wide potential region below 0.7 V(vs.SCE) and inhibited the oxidation of serine.At higher potentials,the serine molecules could be oxidized directly to yield the main product CO2 species.As the pH decreased in the spectroelectrochemical cell during serine reactions,the acidic serine species also detected.The present study revealed the interaction of serine with Pt electrode surface,and suggested a possible reaction mechanism of serine on Pt electrode surface in neutral solutions.