NOVEL PROPERTIES OF DISPERSED PT AND PD THIN-LAYERS SUPPORTED ON GC FOR CO ADSORPTION STUDIED USING IN-SITU MS-FTIR REFLECTION SPECTROSCOPY

The adsorption of CO on dispersed thin layers of platinum and palladiu m supported on glassy carbon (Pt/GC and Pd/GC) was studied using in si tu multi-step FTIR spectroscopy (MS-FTIRS), Novel properties of the di spersed Pt and Pd thin layers with respect to CO adsorption have been observed for the first time. In comparison to the adsorption of CO on smooth Pt and Pd surfaces, the IR features of CO adsorbed on Pt/GC and Pd/GC electrodes become abnormal, consisting mainly in (1) the direct ion of the IR band being inverse, (2) the intensity of the IR band bei ng enhanced significantly with an enhancement factor of 20 for linearl y bonded CO on Pt/GC and 26 for bridge bonded CO on Pd/GC, and (3) the FWHM of the IR band being broadened by about 6-9 cm(-1). The abnormal optic properties of the dispersed Pt and Pd thin layers with respect to CO adsorption were attributed to the particular structure of the th in layers, which is undergoing further investigation.