Toward selective electrochemical “E-tongue”: Potentiometric DO sensor based on sub-micron ZnO–RuO2 sensing electrode

摘要: Abstract Planar dissolved oxygen (DO) sensors based on thick-film ZnO–RuO2 sensing electrodes (SEs) with different mol% of ZnO were prepared the alumina substrates using a screen-printing method and their structural electrochemical properties closely studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive analysis (EDX), impedance (EIS) (EDS) techniques. Structural ZnO–RuO2–SEs have been investigated. Interference testing ascertained that DO sensor sub-micron ZnO–RuO2-SE is insensitive to presence various ions including Cl−, Li+, SO42−, NO3−, Ca2+, PO43−, Mg2+, Na+ K+ within concentration range 10−7 10−1 mol/L for measurement from 0.5 8.0 ppm in test solution at temperature 11–30 °C. These salts had practically no effect sensor's output potential difference response, whereas Br− some effects more than 10−3 mol/L. The relationship between was found be relatively linear maximum sensitivity −50.6 mV per decade achieved 20 mol% 7.35 pH. response recovery time pH changes planar device 10 25 s, respectively, 25 °C, same about 60 s. It has also demonstrated appropriate amounts mixed RuO2 nanostructures not only improves structure developed SE but enhances device's performance.