WANG Zheng ¹, LI Yuehua ¹, DAI Lei ², WANG Ling ¹, MENG Weiwei ¹
(1. School of Chemical Engineering, North China University of Science and Technology, Tangshan 063210, Hebei, China; 2. School of Materials Science and Engineering, North China University of Science and Technology, Tangshan 063210, Hebei, China)

Abstract: Bi₄V₂O₁₁ solid electrolyte, with high ionic conductivity at low and medium temperatures, was prepared by using solid-state reaction method, for application in a mixed-potential NH3 sensor using CuV₂O₆ as the sensitive electrode. Phase composition microscopic morphology of the samples was analyzed by using X-ray diffractometry (XRD), scanning electron microscopy (SEM) and energy spectroscopy (EDS). The conductivity of Bi₄V₂O₁₁ was higher than that of the conventional oxygen ion conductor YSZ at low and medium temperatures (300–600 ℃). The sensor, with Bi₄V₂O₁₁ as the solid electrolyte and CuV₂O₆ as the sensitive electrode, was capable of detecting 10–300 ppm NH₃, in the temperature range of 300–500 ℃, while the sensor based on YSZ as solid electrolyte shows significant performance degradation in the temperature range of 300–350 ℃. The sensor has the highest sensitivity (−59.15 mV/decade) at 400 ℃, which is superior to the one based on YSZ as solid electrolyte under the same condition (−42.89 mV/decade). The sensor has a stable response, with the logarithmic values showing a good positive relationship.
Key words: solid electrolyte; Bi₄V₂O₁₁; NH₃ sensor; mixed potential type