Ultrasensitive gas sensor based on 3D assembled SnS₂/SnO₂ nanoflowers for NO₂ detection at room temperature

Nanostructures of SnO₂ and SnS₂ have been extensively studied for gas sensor application, but individual material faces some limitations such as low detection limits, poor selectivity, and high-power consumption. Nanohybrids of SnO₂ and SnS₂ are expected to achieve high sensing response at low temperatures, but their synthesis is challenging due to the complex processes. Herein, we synthesized SnS₂ flower-like nanostructures decorated with SnO₂ nanoparticles for enhanced gas-sensing performance via one-pot hydrothermal method using tin (IV) chloride pentahydrate and thiourea as precursors. By controlling the ratio of precursors, two phases of SnO₂ and SnS₂ were simultaneously obtained. The functionalizing effect of SnO₂ nanoparticles on the morphology, structure and gas-sensing properties of SnS₂ was systematically studied. Additionally, the impact of moisture on the sensing behaviors is investigated meticulously. On top of that, the synergetic effect of n-n SnS₂/SnO₂ junction is explicated in gas-sensing mechanism. These findings offer a feasible way to construct scalable and effective NO₂ gas sensors for real-world applications.