SPECULAR REFLECTIVITY STUDY OF CO ADSORBED ON A PLATINUM-ELECTRODE INACIDIC SOLUTION

The adsorption behaviour of CO on a Pt electrode was investigated in 1 M HClO4 solution by the use of the in situ specular reflectance metho d, Simultaneous measurement of the reflectivity of the Pt electrode an d the suppressed current of hydrogen adsorption enabled us to find the relation between the reflectivity change and the coverage of adsorbed CO. The reflectivity was found to be dependent on the amount of cover age. In the low coverage region, it increased with the increase of the coverage, while in the high coverage region, it decreased rapidly. Th e reflectivity profile dependence on CO coverage suggests the presence of more than two different types of adsorbed CO. The present results are in accordance with the results obtained with IR measurements, whic h suggest the presence of reflection absorption spectroscopic inactive CO.