US EPA

1205562 

Journal Article 

INSITU FTIRS FEATURES DURING OXYGEN-ADSORPTION AND CARBON-MONOXIDE OXIDATION AT A PLATINUM-ELECTRODE IN DILUTE ALKALINE-SOLUTIONS 

Sun, SG; Chen, AC 

1992 

1 

Journal of Electroanalytical Chemistry and Interfacial Electrochemistry
ISSN: 0022-0728 

323 

1-2 

319-328 

WOS:A1992HZ47200019 

Oxygen adsorption and CO oxidation at a Pt electrode in dilute alkaline solutions were studied using the single-potential alteration Fourier transform IR spectroscopy (SPAFTIRS) technique. The results demonstrated that the concentration of OH- in solution plays an important role in the oxidation of CO(ad) and the retention of the CO2 product of this oxidation. The band due to the CO2 asymmetrical stretch will appear in spectra only when OH- species near the Pt surface in the thin layer between the electrode and the IR window have reached a very low concentration. The experimental data reported here show that CO(ad) may be attacked by OH- species in solution even in the potential region of hydrogen adsorption. In a concentrated base solution the negative-going peak of the CO(ad) bipolar band corresponding to IR absorption by CO(ad) at the sample potential disappears rapidly from the spectra with increasing sample potential, and no CO2 band is observed. During oxygen adsorption and CO oxidation the FTIR spectra are dominated by a curved region between 3000 and 1700 cm-1 and a progressive increase in the intensity of a band near 1650 cm-1, which is defined as "OH- loss structure" and is due to the concentration variation of components, i.e. the loss of OH- and the production of H2O species in the thin layer.