Luminescent Probes of Charge Transport in Modifying Layers on Electrodes

146 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988.The goals of this project are aimed at the investigation of charge transport among redox centers bound in polymer films on electrodes. Luminescent probes were used as an indicator of the charge transport process for the system of interest. The signals were then detected by spectroscopic methods. The advantage of spectroscopic methods is that they provide information about electrochemical systems which is not directly available in strictly electrochemical experiments.The energy transfer dynamics of the system of Ru(bpy)\sb3\sp{2+} immobilized in poly(styrene sulfonate) film has been investigated. A relatively small amount of Co(bpy)\sb3\sp{3+} was introduced into the system as a quencher to evaluate this value. Through this study, the ideas developed by Majda about the dynamics of the system were confirmed. The major conclusion is that the electron transport process is controlled by the counterion diffusion.A new approach based on photosensitization was proved to be effective in detection of i\sb{\rm E} and D\sb{\rm E} for polymer-modified electrodes. The study system was quaternized poly(vinylpyridine) with ferricyanide as redox centers. A rhodamine B isothiocyanate labeled poly(ethyleneimine) was constructed as the dye layer and hydroguinone was the supersensitizer. Different values of photocurrent were obtained by changing the intensity of the light source. One can extrapolate to infinite light intensity from the plot of 1/photocurrent vs. 1/light intensity to obtain a current equal to i\sb{\rm E}. The D\sb{\rm E} was found to be in the order of 10\sp{-8} cm\sp2/sec, and are in the neighborhood of that measured by steady-state voltammetry of the same experimental system.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Electrocatalytic oxidation of vitamin B6 on a chemically modified electrode

[[abstract]]The electrocatalytic oxidation of vitamin B6 (pyridoxine hydrochloride) was demonstrated on a Nafion/lead ruthenate pyrochlore modified electrode (designated as NCME) by cyclic voltammetry. The catalytic activity of vitamin B6 was explored in terms of the higher oxidation state of ruthenium species, i.e., Py-RuIV/RuVI in the pyrochlore network (Py). The mediated mechanism was derived by Michaelis-Menten kinetics. The calculated kinetics values by direct Michaelis-Menten method are Michaelis-Menten rate constant (Km) = 4.05 mmol dm-3, catalytic rate constant (k c) = 2.05×10-1 s-1, and heterogeneous electro- chemical rate constant (k'ME) = 4.09×10-2cm s-1.[[fileno]]2030228010014[[department]]資訊工程學