Ultrasensitive and ultrafast recovery detection of NO2 at room temperature enabled by VS4/SnS2 hierarchical structure

Tin disulfide (SnS 2 ) nanoplates demonstrate remarkable potential in NO 2 detection due to their unique physical affinity to NO 2 . However, SnS 2 nanoplate-based sensors suffer from high operating temperatures, inadequate sensitivity, and slow recovery due to intrinsic low conductivity and self-stacking issues. To address these challenges, we fabricated vanadium tetrasulfide/SnS 2 (VS 4 /SnS 2 ) composites via a facile hydrothermal method. Results reveal that the addition of VS 4 significantly reduces the resistance of SnS 2 -based sensor. The sensitivity (1.64 ppm −1 ) of the optimized VS 4 /SnS 2 (1:1) sensor to 1 −5 ppm NO 2 is 546.67 times higher than that of the pristine VS 4 sensor. The sensor exhibits ultrafast complete recovery (2.25 s) and a low limit of detection (90 ppb) at 25 ℃. In addition, the VS 4 /SnS 2 (1:1) sensor displays reliable repeatability, outstanding selectivity and long-term stability. These breakthroughs originate from the formation of n-n junctions and a unique three-dimensional hierarchical structure. This work demonstrates a scalable approach for developing highly sensitive and rapid SnS 2 -based NO 2 sensors operating at room temperature.