Sr doped SnS2 microflowers with rich S-vacancies for enhanced NO2 response: A combined experimental and computational study

The construction of high-performance sensitive materials is a basis for excellent sensors. Among prior SnS2-based sensors, high sensing performance often accompanies high operating temperatures or expensive costs, which limits their practical use. Herein, we employed Sr doping and NaBH4 treatment strategies to increase the S-vacancies content in the SnS2 microflowers. Particularly, this composite sensitive material shows large specific surface area, low crystallinity and rich S-vacancies content, which enables this sensor excellent sensing properties toward NO2, with a response of 4.7 toward 5 ppm NO2 at 100 degrees C. In addition, this sensor has a low detection limit for NO2 as low as 0.2 ppm, which is a lower value compared to many SnS2-based NO2 sensors as reported. XRD, SEM, TEM, EPR and BET characterization combined with density functional theory (DFT) calculations are adopted to illustrate the enhancement mechanism toward NO2 of the composite sensitive materials fabricated in this work. This study provides new ideas and scientific basis for the construction of metal sulfide based NO2 sensors, which has important theoretical significance and application value.