Solid Electrolyte Type NH₃ Sensors Based On Composite Sensing Electrodes

Solid electrolyte type NH₃ sensors can monitor NH₃ in situ under high temperature and harsh conditions,with high sensitivity and good stability,which have received extensive attention.To date,a variety of sensing materials have been developed for NH₃sensors.Among them,the composite metal oxide sensing electrodes exhibit excellent electrochemistry catalytic activity in complex and harsh environments due to their special structures and flexibility of composition,showing a broad application prospect.The InVO₄-decorated V₂O₅ sensing materials were synthesized by a hydrothermal method,and the mixed potential NH₃ sensors based on yttrium-stabilized zirconia（YSZ）electrolytes were fabricated.The V₂O₅ decorated by InVO₄ can improve the sensing performances to NH₃.When the mole ratio of the InVO₄ and V₂O₅ is 1:3.5,the sensor shows the best sensing performances at 450°C.Meanwhile,the sensor can respond to NH₃ in range of 300～500°C.In addition,the sensor displays good repeatability,moisture resistance,and good anti-interference ability to CH₄,H₂,CO₂ and NO,except NO₂.The layered perovskites La_n+1Ni_nO_3n+1（n=1,2,and 3）sensing electrodes were prepared by a impregnation method,and a series of impedancemetric NH₃ sensors were fabricated using YSZ as solid electrolytes.The results show that the sensor based on the La₂Ni O_4+δ-SE has the higher response values and sensitivities at 550°C.Both|Z|andΘsignals show good linear relationships with NH₃ concentrations.In addition,the coexisting gases such as CO₂,CH₄,H₂ and relative humidity have little interference to the sensor,except NO and NO₂.The Fe-doped In₂O₃ sensing material was prepared by a impregnation method,and the impedancemetric NH₃ sensors using YSZ electrolytes were fabricated.5%mol Fe doping can effectively improve the sensing performances.In the test range of450～600°C,the response values have good linear relationships with the NH₃concentrations,and the sensing performances are the best at 500°C.In addition,the sensor shows good stability,but poor anti-interference ability to NO₂.Figure 40;Table 3;Reference 72...