A mixed-potential gas sensor with heterojunctions based on Co3O4/ZnO/Y2O3 nanocomposite for low concentration H2S detection

This study aimed to develop a H2S gas sensor based on gadolinia-doped ceria (GDC) solid electrolyte and Co3O4/ZnO/Y2O3 ternary nanocomposite. Heterojunctions were formed inside the Co3O4/ZnO/Y2O3 ternary nanocomposite sensing material due to the difference of work function, which effectively adjusted the oxygen vacancy concentration, improved the electrocatalytic activity of the material, and reduced the working temperature. The response showed a piecewise linear correlation with the concentration of H2S, and its sensitivity for 0.2–2 ppm and 2–10 ppm H2S was −6.4 and −36.35 mV/decade, respectively. Furthermore, the sensor exhibited good stability, repeatability, and selectivity to H2S. This study showed that the GDC-based mixed potential sensor with Co3O4/ZnO/Y2O3-SE could be used as a potential sensor for detecting low concentration of H2S.