RuO 2 –IrO 2 solid state micro-liquid film pH sensor based on polymeric precursor method

Abstract

The glass-type electrodes based pH sensors suffer from the weakness of fragility and poor stability in acid/alkali solution. To overcome these disadvantages, a novel solid-state pH sensor based on a RuO₂–IrO₂ H⁺ sensitive electrode via a polymeric precursor method was developed in this paper. The electrochemical performance of pH sensor was tested in different conditions. The experimental results showed that the sensitivity of the pH sensor could reach a high level of 52.0 mV/pH in a wide pH range of 2 ∼ 10. Furthermore, the response of pH sensor was fast and the response time remained less than 2.2 s even under varying pH conditions. The experiment was repeated three times during a period of time, the potential difference of pH sensor was between ±0.3 mV and ±0.9 mV in different pH value solutions, demonstrating its good stability, repeatability, recyclability and small potential drift. The negligible interference of Li⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺, to the proposed pH sensor was also proven experimentally.

Keywords

Solid-state pH sensor ruthenic oxide-iridium oxide polymeric precursor method micro-liquid film

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