A novel TiO2-SnO2 film pH sensor prepared by micro-arc oxidation

In this work, we have used a micro-arc oxidation technique operating in the AC mode to prepare a TiO2-SnO2 film sensitive to pH on a Ti substrate. The microstructure and elemental and material composition of the film was studied. The results show that a porous structure formed on the film surface. XRD indicated that the film contained hydrophilic amorphous TiO2, and XPS showed the formation of oxide SnO2 in the film. TiO2- SnO2/0.5 films doped with 0.5 g/L Na2SnO3 had excellent pH-sensing properties. Performance tests showed that for pH in the range 2-12, the TiO2-SnO2/0.5 films had a sensitivity of 64.60 mV/pH, as well as fast response times, low hysteresis, good stability, and resistance to temperature and interference by ionic impuri-ties. The prepared TiO2-SnO2/0.5 films were used with a commercial pH meter to detect several common fluids with an accuracy of +/- 0.09 pH.

Automated summary

In this study, a TiO2-SnO2 film sensitive to pH was prepared on a Ti substrate using a micro-arc oxidation technique operating in the AC mode. The microstructure and composition of the film were analyzed, revealing the presence of a porous structure and the formation of hydrophilic amorphous TiO2 and oxide SnO2. The doped TiO2-SnO2/0.5 films showed excellent pH-sensing properties, with a sensitivity of 64.60 mV/pH, fast response times, low hysteresis, good stability, and resistance to temperature and interference. The prepared TiO2-SnO2/0.5 films, combined with a commercial pH meter, successfully detected various fluids with an accuracy of +/- 0.09 pH.