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 SnS 2 -based sensors, high sensing performance often accompanies high operating temperatures or expensive costs, which limits their practical use. Herein, we employed Sr doping and NaBH 4 treatment strategies to increase the S-vacancies content in the SnS 2 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 NO 2 , with a response of 4.7 toward 5 ppm NO 2 at 100 °C. In addition, this sensor has a low detection limit for NO 2 as low as 0.2 ppm, which is a lower value compared to many SnS 2 -based NO 2 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 NO 2 of the composite sensitive materials fabricated in this work. This study provides new ideas and scientific basis for the construction of metal sulfide based NO 2 sensors, which has important theoretical significance and application value.