Moderate-temperature operable SO₂ gas sensor based on Zr⁴⁺ ion conducting solid electrolyte

Abstract. A solid electrolyte type sulfur dioxide (SO₂) gas sensor that can operate at moderate temperatures was fabricated using Zr⁴⁺ ion conducting Zr_39/40TaP_2.9W_0.1O₁₂ solid electrolyte with 0.7La₂O₂SO₄ − 0.3(0.8Li₂SO₄ + 0.2K₂SO₄) having a large surface area and Zr metal as the auxiliary sensing electrode and reference electrode, respectively. Since the present sensor showed a quantitative, reproducible and rapid response which obeys the theoretical Nernst relationship even at 400 °C, it is a potential on site SO₂ gas sensing tool operable at moderate temperatures around 400 °C.