Ag intercalated SnS2 with S vacancy and expanded interlayer for enhancing NO2 sensing

Nitrogen dioxide (NO2) is a common gas that can cause irreversible damage to human health, emphasizing the essentiality of developing highly sensitive NO2 sensors with good selectivity and low consumption. Here, a facile in–situ cation exchange method was employed to successfully synthesize interlayer expansion Ag intercalated SnS2 with S vacancies for NO2 gas sensing. The presence of S vacancies strongly improves the electronic structure of SnS2 and significantly facilitates the interaction of NO2 with the sensor. Moreover, the interlayer spacing of SnS2 is expanded by 0.48 Å after Ag intercalation, prompting diffusion behavior of NO2 molecules between the interlayers. Benefiting from the factors above, SnS2–Ag exhibited excellent gas sensing performance for NO2 with a high response to 5 ppm NO2 (response value = 8.37) and detection limits as low as 200 ppb at a low temperature of 100 °C. This work combines defect engineering with interlayer engineering to provide a new perspective for extending the application of SnS2 gas sensors.