Joanna Niedziółka
"Preparation and properties of the electrodes modified with hydrophobic silicate film and redox liquid"

Abstract

Among the many possibilities of the electrodes surface modification the deposition of the redox liquid and silicate film fabrication by the sol-gel process were recently reported. It was expected that the combination of these two approaches might result in a voltametrically stable electrode modified with a large number of the redox active groups exhibiting an efficient electrode process. When it is immersed into the aqueous solution a well defined liquid-liquid interface is formed.

Six new electrodes based on hydrophobic silicate films and conducting ITO nanoparticles or hydrophobic carbon nanofibers are presented. In general two methods of modification were employed. The first uses sol-drop deposition and solvent evaporation. The second involves layer-by-layer deposition of conductive nanoparticles onto the electrode support.

FTIRRAS, AFM and SEM were employed to verify the well developed surface topography and the polymer network formation. Cyclic voltammetry reveals partial blocking of the electrode surface for redox active species present in solution. The voltammetric stability and the efficiency of the electrode process of the deposited redox liquid depend on the electrode preparation. In some cases either voltammetric stability was achieved or the efficiency of the electrode process reaches 10 - 30 %. For the electrode modified with hydrophobic silicate and hydrophobic carbon nanofibers both goals were achieved. The electrodes were also successfully modified with supported redox liquid for example redox probe solution in room temperature ionic liquid. In this case mechanism of the electrode process involving electron transfer followed by ion transfer across the liquid|liquid boundary was elucidated with help of differential pulse voltammetry.