Preparation and Characterization of Titanium Dioxide Nanotube Array/Titanium pH Electrode

A method for rapidly preparing titanium dioxide nanotube array/titanium (TiO2NTAs/Ti) as a pH electrode by using anodization method in a mixed solution containing NH4F and ethylene glycol and water was established. The electrodes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The possible pH response mechanisms were discussed by the hydrophilicity, specific surface area, and surface chemisorbed oxygen (-OH) of the electrodes. Under the optimized conditions including electrolysis voltage of 30 V, a mixed solution containing NH4F (0.5%, w/w) and ethylene glycol and water (9:1, V/V) as electrolyte and anodization time of 10 min, the prepared TiO2NTAs/Ti electrode in Beretan-Robson (B-R) buffer solution (pH=3-11) exhibited an excellent pH response with a sensitivity of (-55.17 +/- 0.28) mV/pH and a correlation coefficient (R-2) of above 0.9966. The results of the ion interference experiments showed that the effect of common ion on the electrode was negligible. The electrode had good stability and was successfully applied to the determination of pH value of vitamin drink and seawater.