Ammonia (NH3) poses significant hazards to human health and the environment, making the development of high-performance NH3 sensors of great importance. This study combines the advantages of SnS2 (high response to NH3) and Ti3C2 (metal-level electrical conductivity and tunable surface properties) to prepare Ti3C2/SnS2 heterojunctions via two methods: vacuum filtration (denoted as Ti3C2/SnS2-F) and one-pot hydrothermal synthesis (denoted as Ti3C2/SnS2-H) and systematically investigates their NH3 sensing performance. Gas-sensing tests demonstrate that Ti3C2/SnS2-F has a wide response range of 10-500 ppm toward NH3. Specifically, it exhibits a response value of 11 to 500 ppm of NH3, a fast response/recovery time of 15 s/44 s, and excellent long-term stability. Ti3C2/SnS2-H demonstrates a good linear response to 10-300 ppm of NH3 and low baseline resistance. Both materials display excellent selectivity for NH3 and solve the problem of incomplete desorption of pure SnS2. First-principles calculations reveal that electron transfer occurs at the interface of Ti3C2 and SnS2, forming a charge-layered structure. The adsorption of NH3 regulates the resistance by changing the carrier distribution, thereby enhancing the electrical signal. This study confirms that the Ti3C2/SnS2 heterojunction is an excellent candidate material for high-performance NH3 sensors, providing a new strategy for the design of gas-sensing materials.
Liu et al. (Tue,) studied this question.