Rongrong Zou, Shulin Zhu, Dingyuan Wang, Jiayuan Xu, Lizhai Zhang
Ammonia (NH3) gas sensors play an essential role in agricultural production, industrial manufacturing, human health protection and environmental monitoring. However, development of the room-temperature NH3-sensing materials with sensitive response remains challenging. In this work, SnS2/Ti3C2Tx composites with S vacancies are prepared by the hydrothermal process in which the introduction of a high concentration of CH4N2S promotes the formation of S vacancies. Compared with SnS2, the optimized SnS2-Ti3C2Tx composites exhibit a response of 71.5% to 300 ppm NH3, enhancement of 90%, as well as excellent reproducibility, long-term stability, and selectivity. During NH3 sensing, SnS2 with S vacancies not only provides more active sites for NH3 adsorption but also exhibits a modified electronic structure of SnS2 with improved NH3 adsorption. Ti3C2Tx, with high electrical conductivity, provides electron-transfer channels. The interfacial heterojunction facilitates charge transport and provides abundant active sites for NH3 adsorption. The results suggest significant potential for designing two-dimensional materials with tunable sensing properties through defect and heterojunction engineering.