CORRELATION OF THE SURFACE STRUCTURE OF THE RuO2/TiAND TiO2 /TiFILMS WITH ELECTROCHEMICAL IMPEDANCE DATA

Abstract

The surface structure and nature of the capacitance formation of RuO2/Ti and TiO2 /Ti films are discussed. The factors affecting the reversibility of the adsorption-desorption processes of oxygen on the surface of RuO2/Ti and TiO2 /Ti films are described. The influence of the geometry of the pore, ruthenium content, thickness of the films, and the capacitance value of oxide films was studied using electron microscopy and electrochemical impedance spectroscopy. The changes in pore content and their geometry depending on Ru concentration are fixed by electron microscopy. The changing capacitance and capacitance dispersion in a wide frequency range was used to obtain 3D images of the film's surface. A scheme of the adsorption-absorption ratio changing in relation to the pore’s structure of the films was proposed. The study of the composition, morphological structure and electrochemical behaviour of RuO2/Ti and TiO2 /Ti films determined the impact of the pore shape of surface films on the adsorption-absorption ratio of oxygen, which regulated technical data of sensors. By changing the capacitance and capacitance dispersion in a wide frequency range, it was proposed to obtain 3D images of the surface. It was found that decrease of DEL capacitance has following relationships: large V-shaped pores on the boundary of titanium base and oxide film and on the surface of film > small V-shaped pores on the boundary of titanium base and oxide film, and large pores on the surface of film > rectangular-shaped pores on the boundary of titanium base and oxide film and small V-shaped pores on the surface of film. The formation of the pore geometry and surface structure is dependent on the ration of ruthenium and the thickness of films. So, it is possible to change the morphological and electrochemical properties of sensors by the regulation of ruthenium content.