Analysis of an Impedance Model for Porous Semiconductor Electrodes

Abstract

The main aim of this work was to analyze an impedance model for porous semiconductor electrodes consisting of spherical particles. The model should make it possible to analyze the flatband potential for this type of electrodes. The analysis was conducted by simulating the model in MATLAB®. Cyclic voltammetry and electrochemical impedance spectroscopy was performed on titanium oxide, TiO2 P25, anodized titanium and some iridium tin oxides, Ir(1-x)SnxO2. The aim was to use the experimental data as a reference and compare the simulated data with the experimental results. This could not be done because the recorded data for the oxides were too strongly influenced by the support material. The supports tested in this work were Au, Ti and ITO. The simulations show that the capacitance of the models spherical particle is only weakly dependent on the particles surface potential. This indicates that this one-dimensional version of the model might not be sufficient to analyze the spherical particles. However, another analysis method for investigation of Mott-Schottky behavior for porous electrodes was confirmed by the result for the anodized titanium.