Spectro-electrochemical studies of the electrode-solution interface and high nuclearity metal clusters
Abstract
The joint application of Fourier transform infrared spectroscopy and thin layer electrochemistry has been used to probe the electrode-solution interface and to examine the vibrational spectro-electrochemistry of several metal clusters. Comparison of the surface and cluster results has allowed for direct evaluation of the surface-cluster analogy. The first portion of this work (Chapters 3 and 4) have focussed on surface confined species in aqueous media. The second portion examined surface confined species in non-aqueous solvents (Chapter 5 and Appendix C). The final portion examined the vibrational spectro-electrochemistry of several metal clusters in solution. In the first portion, a flowcell was used to monitor the concentration of CO$\sb{\rm ads}$ on a Pt electrode during the continuous oxidation of CO and to eliminate vibrational bands from solution OCN$\sp-$ and N$\sbsp{3}{-}$ to allow for the unhindered observation of surface confined OCN$\sp-$ and N$\sbsp{3}{-}$. Using the oxidation of CO as a model system it was shown that a faradaic reaction can be sustained and observed under steady state conditions by forcing reactant containing solution through the thin layer. (Chapter 3) In another study flow through the thin layer was employed to keep the concentration of solution OCN$\sp-$ and N$\sbsp{3}{-}$ constant in the thin layer, resulting in the perfect cancellation of these solution phase I.R. bands during a PDIR experiment. The second portion examined CO$\sb{\rm ads}$ on Pt and Ni electrodes. For a CO covered Pt electrode the $\nu\sbsp{\rm CO}{\rm t}$ and the site occupancy were found to be very dependent upon the size and Lewis acid strength of the cation employeed as a supporting electrolyte. The last portion resulted from a collaboration with Professor Dahl's group at U.W.-Madison. They provided a number of large Pt and Ni clusters. All of the Pt clusters examined exhibited a large number of stable oxidation states. This made them excellent subjects for the evaluation of the surface-cluster analogy.
Degree
Ph.D.
Advisors
Weaver, Purdue University.
Subject Area
Analytical chemistry
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