Preparation of SnS₂/MoS₂with p-n heterojunction for NO₂sensing

Conventional metal sulfide (SnS₂) gas-sensitive sensing materials still have insufficient surface area and slow response/recovery times. To increase its gas-sensing performance, MoS₂nanoflower was produced hydrothermally and mechanically combined with SnS₂nanoplate. Extensive characterization results show that MoS₂was effectively integrated into SnS₂. Four different concentrations of SnS₂-MoS₂composites were evaluated for their NO₂gas sensitization capabilities. Among them, SnS₂-15% MoS₂at 170 °C demonstrated the greatest response values to NO₂, 7.3 for 1 ppm NO₂, which is about three times greater than the SnS₂sensor at 170 °C (2.58). The creation of pn junctions following compositing with SnS₂was determined to be the primary reason for the composite's faster recovery time, while the heterojunction allowed for the rapid separation of hole-electron pairs. Because the MoS₂surface has multiple vacancy defects, the adsorption energy of these vacancies is significantly higher than that of other places, resulting in increased NO₂adsorption. Furthermore, MoS₂can serve as active adsorption sites for SnS₂micrometer sheets during gas sensing. This study may help to build new NO₂gas sensors.