A ruthenium oxide and iridium oxide coated titanium electrode for pH measurement

This paper reports the pH sensing capability of a ruthenium oxide (RuO2) and iridium oxide (IrO2) coated titanium (ROIOT) electrode. The characterization results indicated that the ROIOT electrode had a cracked morphology. The RuO2 and IrO2 particles were decorated on the surface of the electrode. The ROIOT electrode showed near-Nernstian sensitivity of −50.8 mV pH−1, with a wide detection range of pH 2–12. The response time was 4.0–13.5 s, which was fast and very sensitive to the pH change. The ROIOT electrode also demonstrated great detection reversibility and stability in various pH conditions. In the long-term experiment of 30 d, potential measurements using the ROIOT electrode had a minor fluctuation of 1.5 mV d−1. The practical application of the ROIOT electrode was demonstrated by measuring the pH values of various buffer solutions and complex samples. With the advantages of low cost and simple production, it is believed that the ROIOT electrode could be a promising candidate for use as a sensing material for pH sensor development.