TY - JOUR
T1 - The electrochemical oxidation of xylitol on Pt (1 1 1) in acid medium
AU - Matos, João P.F.
AU - Proença, Luis
AU - Lopes, M. Irene S.
AU - Fonseca, Inês T.E.
N1 - Funding Information:
The authors thank FCT (Fundação para a Ciência e Tecnologia) for financial support to CECUL – Research Unit POCTI/301/2003 (FEDER). The authors also thank A. Rodes from the University of Alicante for all the facilities and guidance in the FTIRS experiments.
PY - 2004/9/15
Y1 - 2004/9/15
N2 - A voltammetric and spectroscopic study of the oxidation of xylitol, in acid medium, on a platinum single crystal, Pt (111) and on polycrystalline platinum, Pt (poly), electrodes is presented in this paper. The superior electrocatalytic activity of the Pt (111) electrode surface in comparison with that of the Pt (poly) was clearly demonstrated. The oxidation of xylitol on the Pt (111) electrode surface has been studied by varying the scan potential rate and the xylitol concentration. The CVs show a shoulder and a well-defined anodic peak. It was concluded that both peaks are due to an irreversible one-electron transfer reaction and that the most positive peak presents a diffusion control. The reactions are of the order of 1/2 with respect to the initial polyol concentration. FTIRS data of the system Pt (111) in 0.1 M HClO4+0.01 M xylitol, either in water or D2O, have shown the existence of bands corresponding to adsorbed CO, bridge and linearly bonded, both involved in the surface poisoning in the range from 0.325 to 0.625 V vs. reversible hydrogen electrode (RHE). At E > 0.625 V vs. RHE, bands, which may be attributed to acid groups and to a lactone, have been observed. Thus, the rather probable reaction products are, besides CO2, xylonic acid (and the corresponding lactone, xylonolactone) and other short-chain aliphatic carboxylic acids resulting from the breaking of the initial molecular carbon skeleton.
AB - A voltammetric and spectroscopic study of the oxidation of xylitol, in acid medium, on a platinum single crystal, Pt (111) and on polycrystalline platinum, Pt (poly), electrodes is presented in this paper. The superior electrocatalytic activity of the Pt (111) electrode surface in comparison with that of the Pt (poly) was clearly demonstrated. The oxidation of xylitol on the Pt (111) electrode surface has been studied by varying the scan potential rate and the xylitol concentration. The CVs show a shoulder and a well-defined anodic peak. It was concluded that both peaks are due to an irreversible one-electron transfer reaction and that the most positive peak presents a diffusion control. The reactions are of the order of 1/2 with respect to the initial polyol concentration. FTIRS data of the system Pt (111) in 0.1 M HClO4+0.01 M xylitol, either in water or D2O, have shown the existence of bands corresponding to adsorbed CO, bridge and linearly bonded, both involved in the surface poisoning in the range from 0.325 to 0.625 V vs. reversible hydrogen electrode (RHE). At E > 0.625 V vs. RHE, bands, which may be attributed to acid groups and to a lactone, have been observed. Thus, the rather probable reaction products are, besides CO2, xylonic acid (and the corresponding lactone, xylonolactone) and other short-chain aliphatic carboxylic acids resulting from the breaking of the initial molecular carbon skeleton.
KW - Electrooxidation
KW - FTIR spectroscopy
KW - Pt (1 1 1)
KW - Pt (poly)
KW - Xylitol
UR - http://www.scopus.com/inward/record.url?scp=4344671860&partnerID=8YFLogxK
U2 - 10.1016/j.jelechem.2004.04.016
DO - 10.1016/j.jelechem.2004.04.016
M3 - Article
AN - SCOPUS:4344671860
SN - 1572-6657
VL - 571
SP - 111
EP - 117
JO - Journal of Electroanalytical Chemistry
JF - Journal of Electroanalytical Chemistry
IS - 1
ER -