Role of Pt-probe pseudo-reference electrode in impedance measurements of Pt and polyaniline (PANI) modified Pt electrodes

Role of Pt-probe pseudo-reference electrode (PRE) capacitively connected to reference electrode was examined in impedance measurements of reduced (insulating) and oxidized (conducting) forms of PANI thin film modified Pt and pure Pt electrodes. It was shown that in dependence on the shunting capacitor values, and particularly on geometric position of PRE vs. working and reference electrodes, presence of PRE induced certain content of experimental artefacts in all measured impedance spectra. Experimental artefacts being manifested as interrelated high-frequency capacitive and inductive/resistive impedances were much more prominent for lower impedance electrodes (oxidized form of PANI film) and should be taken into account using appropriate transfer function involving experimental artefacts.