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Potential dependence of the stretching frequency of carbon monoxide bound to the surface of platinum dispersed in an electrode-confined redox polymer

Journal Article · · Inorg. Chem.; (United States)
DOI:https://doi.org/10.1021/ic00224a028· OSTI ID:5896597

Variation in the electrochemical potential of the electrode results in a change in the stretching frequency of CO bound to elemental Pt dispersed in an electrode-confined redox polymer, (PQ/sup 2+/+/)/sub n/, derived from an N,N'-dialkyl-4,4'-bipyridinium monomer. The stretching frequency of the CO, about 2000 cm/sup -1/, can be monitored by transmission infrared spectroscopy using a Fourier transform infrared (FTIR) spectrometer and moves to lower values with movement of the potential to more negative values. Spectroelectrochemical studies were conducted by using an IR-transparent n-Si/((PQ/sup 2+/+/Pt(CO)/sub x/)/sub n/) electrode assembly in an electrochemical cell with the derivatized surface exposed to the electrolyte solution. Experiments have been carried out with both natural-abundance and 99% /sup 13/C-enriched CO, and the potential dependence is the same, about 20 cm/sup -1/ V/sup -1/, over the potential range studied, approximately 0.0 to -1.4 V vs. Ag/sup +//Ag in CH/sub 3/CN/2 M LiClO/sub 4/. The stretching frequency of natural-abundance CO in the same assembly has been studied in H/sub 2/O/3 M LiCl and shows a slightly larger potential dependence, about 35 cm/sup -1/ V/sup -1/, in the range -0.2 to -1.0 V vs. AgCl/Ag. The data for the CO bound to the Pt dispersed in the polymer is in accord with similar data obtained for CO bound to smooth Pt electrode surfaces.

Research Organization:
Massachusetts Institute of Technology, Cambridge
OSTI ID:
5896597
Journal Information:
Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 25:4; ISSN INOCA
Country of Publication:
United States
Language:
English