Edge-exposed MoS₂ nanospheres assembled with SnS₂ nanosheet to boost NO₂ gas sensing at room temperature

SnS₂ nanosheets (NSs) have become an ideal candidate for high performance gas sensors due to their unique sensing properties. However, the restacking and aggregation in the process of sensor manufacturing have great influence on the gas sensing performance. In this study, we synthesized a novel heterojunction of the flower-like porous SnS₂ NSs with edge exposed MoS₂ nanospheres via a facile hydrothermal method and sensitive response has achieved at room temperature (27℃). After functionalization, the SMS-Ⅱ showed excellent response (Ra/Rg = 25.9-100 ppm NO₂), which is 22.3 times higher than that of the pristine SnS₂ NSs. The sensor also has the characteristics of short response time of 2 s, excellent base line recovery (28.2 s), long-term stability and reliability within 16 weeks, good selectivity and low detection concentration of only 50 ppb. The p-n heterojunction formed between the edge-exposed spherical MoS₂ and the 3D flower-like SnS₂ NSs has a synergistic effect, providing a highly active sites for the adsorption of NO₂ gas, which greatly enhance the sensitivity of the sensor. Simple fabrication and excellent gas sensing performance of the SnS₂/MoS₂ heterostructure nanomaterials (NMs) will highly effective for commercial gas sensing application.