Improving the stability of an amperometric ammonia sensor based on BaZr0.8Y0.2O3-δ electrolyte with a volatile B2O3 sintering additive

Yttrium-doped BaZrO3 (BZY) shows great potential as a new solid electrolyte for high-temperature NH3 sensing applications. However, it is difficult to obtain a dense BZY electrolyte due to the refractory nature of this material. For this paper, an amperometric NH3 sensor based on a BaZr0.8Y0.2O3-delta (BZY20) electrolyte was proposed, and volatile B2O3 was added to improve the density of BZY, which was essential to enhance the sensitivity and stability of the sensor. The effects of B2O3 on the density, morphology, and conductivity of the electrolyte were investigated. Furthermore, the influence of the density of BZY20 on the sensitivity and stability of the sensor was analyzed. It was found that the sensitivity and stability were significantly improved by the enhancement of the conductivity. In addition, the sensor could reach a detection limit as low as 2.5 ppm for NH3 at 450 celcius and showed good selectivity, repeatability, and long-term stability.