Enhanced sensing performance of mixed potential ammonia gas sensor based on Bi0.95Ni0.05VO3.975 by silver

Bi 0.95 Ni 0.05 VO 3.975 with flower-like structure was prepared by the hydrothermal method. Mixed potential type NH 3 sensors were fabricated using Bi 0.95 Ni 0.05 VO 3.975 as sensing electrode and La 10 Si 5.5 Al 0.5 O 27 as electrolyte. The sensing performance of the sensors was tested in the temperature range of 500–650 °C. The test results show that the sensor exhibits excellent NH 3 sensing performance. The response signals linearly depend on the logarithm of the NH 3 concentrations. The sensor also shows a good stability and reproducibility. The sensor displays a good anti-interference ability to CO 2 , H 2 and CH 4 . However, NO 2 leads to a great influence on the response potential of the sensor. The effect of introduction of Ag into sensing electrode on sensor performances was investigated. Compared with the sensor based on Bi 0.95 Ni 0.05 VO 3.975 , the sensor with the Ag modified Bi 0.95 Ni 0.05 VO 3.975 sensing electrode shows much higher sensitivities. More importantly, the interference from NO 2 is completely eliminated and the selectivity of the sensor is significantly improved, which can be attributed to the NO 2 adsorption ability of the sensing material being depressed by the introduction of Ag. This strategy provides a new idea to improve the selectivity of NH 3 sensor besides sensitivity.