An electrochemically cleanable pH electrode based on an electrodeposited iridium oxide-ruthenium oxide-titanium composite.

Biological contamination is an important issue in environmental pH detection, and our prepared electrochemically cleanable electrode may be an effective solution. By electrodepositing an iridium oxide-ruthenium oxide composite on a titanium sheet substrate, the electrode shows a sensitivity of 59.4 mV per pH in the pH range of 2-12 with high reproducibility, low hysteresis, high selectivity and high stability. It is worth mentioning that the electrode was proved to be electrochemically cleanable from biological contamination. When the cleaning time was 30 minutes, the electrode sensitivity rose from 50 to 58 mV per pH. Furthermore, the pH sensor, assembled from the prepared iridium-ruthenium oxide electrode and a home-made Ag/AgCl electrode, has similar electrode properties to those of commercial glass electrodes, but is also mechanically strong and electrochemically cleanable, which is promising for long-term deployment in natural environments.