Novel Methods Of Fluorescence (Reflectance) Spectroelectrochemistry And Electrochemical Quartz Crystal Microbalance: Preliminary Applications

Spectroelectrochemistry (SEC), which is the combination of spectroscopy and electrochemistry, is of higher selectivity than conventional electrochemisty and feasible to investigate the electrochemical process at the molecular or atomic level. Electrochemical piezoelectric quartz crystal microbalance (EQCM) provides a useful tool for in situ measuring concurrent mass loading on the electrode surface by using a piezoelectric crystal sensor in electrochemical processes. Piezoelectric Spectroelectrochemistry, which combines piezoelectric sensor with Spectroelectrochemistry, can provide piezoelectric, spectral and electrochemical information in one experiment and thus lead to less ambiguity in the description of a practical electrochemical process.The studies in the thesis are summarized as follows:1. The recent progress of Spectroelectrochemistry and piezoelectric Spectroelectrochemistry researches is reviewed2. The theory underlying the single potential-step chronofluorometric (SPS/CF) determination of heterogeneous electron transfer rate constants using a long optical pathlength spectroelectrochemical cell has presented. The resulting expressions have been verified via experiments of o-tolidine oxidation at a platinum electrode in 1 M HC1O4+ 0.5 M HAc medium. Results show that a modification of the present model tofit cyclic voltammetry is also feasible.3. A simultaneous EQCM-fluorescence method has been proposed as a novel and informative tool for the study of adsorption/desorption and oxidation for vitamin Be (pyridoxol) at a polycrystalline Au electrode in aqueous KOH. In addition, the voltammetrically electrogenerated fluorescence is proposed as a new and sensitive method for assay of pyridoxol with satisfactory results.4. Piezoelectric reflectance spectroelectrochemistry (PRSEC), a new technique of SEC in combination with QCM detection, has been proposed. The simultaneous measurements of reflectance spectra on the electrode surface, the QCM frequency and resistance as well as the electrochemical signals have been performed during growth and redox switching of polypyrrole and poly(N-methylpyrrole) film. This technique can provide in situ multidimensional information in an electrochemical process and is thus recommended for wider applications to surface/interface phenomena studies.