Selectivity of an Ag/BTO-Based Nanocomposite as a Gas Sensor Between NO 2 and SO 2 Gases.

The novel Ag/BTO/TiO 2 nanocomposite was assessed for its gas-sensing capabilities toward hazardous gases NO 2 and SO 2 . It exhibited p-type behavior with increasing resistance for SO 2 with a response and recovery time of ∼5 and ∼2 s, respectively, switching to n-type behavior when exposed to NO 2 with a response and recovery time of ∼20 and ∼250 s, respectively. Analyte gas concentrations from 0 to 220 ppm were taken for analysis. Selectivity analysis at room temperature revealed NO 2 's superior response of ∼20% above 180 ppm, compared to SO 2 's < 3% response at 180 ppm. NO 2(VC) achieved its highest response (∼45%) at 30 ppm and remained constant above 80 ppm, while SO 2(VC) peaked at ∼30% at 60 ppm but declined with increasing flow rates. Further, the increasing temperature led to an amplified response for NO 2 , whereas SO 2 showed an increase in response after 180 °C. SO 2(VC) exhibited a significant response of ∼70% from 140 °C onward. Additionally, NO 2(VC) showed distinct peaks at 160, 250, and 290 °C with responses of 50, 65, and 80%, respectively. The calculated limit of detection values were 236 ppm for NO 2 , 644.07 ppm for SO 2 , 401.32 ppm for NO 2(VC) , and 496.86 ppm for SO 2(VC) .