Hierarchical SnS₂/SnO₂ Heterostructures for Synergistic NO₂ Sensing under Ambient Conditions

Precise detection and quantification of toxic and hazardous gases under ambient conditions are essential for environmental monitoring and human health protection. In this key aspect, effective monitoring is crucial and relies on the deployment of reliable sensors that offer high sensitivity, excellent selectivity, and long-term stability. The current work investigates the sensing behavior of the SnS 2 /SnO 2 nanocomposite for NO 2 detection at room temperature. The impact of the flower-like SnS 2 structure coupled with the SnO 2 particles (SnS 2 /20 wt % SnO 2 ) enhances the prompt response time of 135 s to 2 ppm of NO 2. The proposed gas sensing mechanism explains the synergy of electronic and geometric effects along with the formation of heterojunctions. The fabricated sensor showed a 348.4% increase in sensing response compared to pristine SnS 2 . Additionally, minimal degradation (96% stability) is noted after 30 days of air exposure. These results demonstrate that this is an effective technique to increase the utility of SnS 2 as a room-temperature gas sensor.