New Electrochemical Insights Gained From Use Of Fourier Transform Based Instrumentation

School of Chemistry, Monash University

Friday 10^th June 2005, 3.30PM, Seminar Room AR103, Graduate Research Centre.

An integrated instrumental, theoretical and experimental approach to Fourier Transform Voltammetry has been developed. Via this strategy, the techniques of sinusoidal, square wave and pulse voltammetry, as well as impedance spectroscopy and many other techniques are all represented as a summation of sine waves of known amplitude and frequency, superimposed onto a DC ramp. From this perspective, the output of numerous voltammetric techniques for a given mechanism differ only in their patterns of behaviour exhibited as a function of frequency in the power spectrum and in the harmonic analysis made available by a Fourier transform-inverse Fourier transform sequence of operations. Use of identical protocols for analysis of both experimental and simulated data along with recognition of intuitively obvious patterns of behaviour that reflect the nuances of the electron transfer process, uncompensated resistance and background currents provides a powerful strategy for complete characterization of an electrode process. Importantly, well known advantages of the widely employed technique of DC cyclic voltammetry are retained. Examples of waveforms that generate patterns of behaviour that include unusual kinetic selectivity such as full discrimination against reversible or irreversible processes and the ability to minimize background current and distinguish uncompensated resistance and electrode kinetic effects and exploit non-linearity will be given for solution soluble electroactive species and for surface confined electrode processes. Prospects for generation of hitherto unused waveforms that provide optimized forms of voltammetry that specifically achieve a targeted outcome will be considered.

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