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.
Neri G. First fifty years of chemoresistive gas sensors. Chemosensors. 3(1): 1−20.
Sirelkhatim, A., Mahmud, S., Seeni, A., Kaus, N. H. M., Ann, L. C., Bakhori, S. K. M. ... & Mohamad D. Review on zinc oxide nanoparticles: antibacterial activity and toxicity mechanism. Nano-micro letters. 2015. 7(3): 219−242.
Cheng S., Liu H., Hu S., Zhang D., & Ning, H. A survey on gas sensing technology Xiao Liu. Sensors. 2012. 12: 9635−9665.
Zhang J., Hu J. Q., Zhu F. R., Gong H. &O’shea S. J. Quartz crystal microbalance coated with sol-gel-derived thin films as gas sensor for no detection. Sensors, 2003. 3 (10): 404−414.
Wisitsoraat A., Tuantranont A., Comini E., Sberveglieri G. &Wlodarski W. (2009). Characterization of n-type and p-type semiconductor gas sensors based on NiOx doped TiO2 thin films. Thin Solid Films. 517(8): 2775−2780.
Yamazoe N., &Shimanoe K. Theory of power laws for semiconductor gas sensors. Sensors and Actuators B: Chemical. 2008. 128(2): 566−573.
Maskell, W. C. Inorganic solid state chemically sensitive devices: electrochemical oxygen gas sensors. Journal of Physics E: Scientific Instruments. 1987. 20(10). 1156.
Sardarinejad A., Maurya D. K. &Alameh K. The pH sensing properties of RF sputtered RuO2 thin-film prepared using different Ar/O2 flow ratio. Materials. 2015. 8(6): 3352−3363.
Fine G. F., Cavanagh L. M., Afonja A. &Binions R. Metal oxide semi-conductor gas sensors in environmental monitoring. Sensors. 2010. 10(6): 5469−5502.
Wang H., Chen L., Wang J., Sun Q. & Zhao Y. A micro oxygen sensor based on a nano sol-gel TiO2 thin film. Sensors, 14(9). 2014. 16423−16433.
Francioso L., Presicce D. S., Siciliano P. &Ficarella A. Combustion conditions discrimination properties of Pt-doped TiO2 thin film oxygen sensor. Sensors and Actuators B: Chemical. 2007. 123(1): 516−521.
Kim Y. D., Seitsonen A. P., Wendt S., Wang J., Fan C., Jacobi K. … &Ertl G. Characterization of various oxygen species on an oxide surface: RuO2 (110). The Journal of Physical Chemistry B. 2001. 105(18): 3752−3758.
Over Y. D., Kim A. P., Seitsonen S. W. & Wendt S. E. Lundgren, M. Schmid, P. Varga, A. Morgante and G. Ertl. Science. 2000. 287(54−57). 1474.
Jakob P. &Schlapka A. CO adsorption on epitaxially grown Pt layers on Ru (0 0 0 1). Surface science. 2007. 601(17): 3556−3568.
Martı́nez-Máñez R., Soto J., Lizondo-Sabater J., Garcı́a-Breijo E., Gil L., Ibáñez J. ... & Alvarez S. New potentiomentric dissolved oxygen sensors in thick film technology. Sensors and Actuators B: Chemical. 2004. 101(3): 295−301.
Harrington D. A. & Den Driessche V. P. Mechanism and equivalent circuits in electrochemical impedance spectroscopy. ElectrochimicaActa. 2011. 56. 8005−8013.
Riabokin O. L., Boichuk A. V. &Pershina K. D. Control of the State of Primary Alkaline Zn–MnO2 Cells Using the Electrochemical Impedance Spectroscopy Method. Surface Engineering and Applied Electrochemistry. 2018. 54(6): 614−622.
Oelgeklaus R., Rose J. &Baltruschat H. On the rate of hydrogen and iodine adsorption on polycrystalline Pt and Pt (111). Journal of Electroanalytical Chemistry. 1994. 376(1−2): 127−133.
Macdonald, D. D. Reflections on the history of electrochemical impedance spectroscopy. ElectrochimicaActa. 2006. 51(8−9):1376−1388.
Kerner Z. &Pajkossy T. On the origin of capacitance dispersion of rough electrodes. ElectrochimicaActa. 2000. 46(2−3): 207−211.
JGabelli J., Feve G., Berroir J. M., Plaçais B., Cavanna A., Etienne B. & Hill R. E. al, Y. Jin, and DC Glattli. Science. 2006. 313. 499.
Sobieszuk P., Pohorecki R., Cygański P. &Grzelka J. Determination of the interfacial area and mass transfer coefficients in the Taylor gas–liquid flow in a microchannel. Chemical engineering science. 2011. 66(23): 6048−6056.