Dual-Synthesis Ti 3 C 2 /SnS 2 for NH 3 Detection: High Sensitivity and Fast Response/Recovery

Ammonia (NH 3 ) poses significant hazards to human health and the environment, making the development of high-performance NH 3 sensors of great importance. This study combines the advantages of SnS 2 (high response to NH 3 ) and Ti 3 C 2 (metal-level electrical conductivity and tunable surface properties) to prepare Ti 3 C 2 /SnS 2 heterojunctions via two methods: vacuum filtration (denoted as Ti 3 C 2 /SnS 2 –F) and one-pot hydrothermal synthesis (denoted as Ti 3 C 2 /SnS 2 –H) and systematically investigates their NH 3 sensing performance. Gas-sensing tests demonstrate that Ti 3 C 2 /SnS 2 –F has a wide response range of 10–500 ppm toward NH 3 . Specifically, it exhibits a response value of 11 to 500 ppm of NH 3, a fast response/recovery time of 15 s/44 s, and excellent long-term stability. Ti 3 C 2 /SnS 2 –H demonstrates a good linear response to 10–300 ppm of NH 3 and low baseline resistance. Both materials display excellent selectivity for NH 3 and solve the problem of incomplete desorption of pure SnS 2 . First-principles calculations reveal that electron transfer occurs at the interface of Ti 3 C 2 and SnS 2, forming a charge-layered structure. The adsorption of NH 3 regulates the resistance by changing the carrier distribution, thereby enhancing the electrical signal. This study confirms that the Ti 3 C 2 /SnS 2 heterojunction is an excellent candidate material for high-performance NH 3 sensors, providing a new strategy for the design of gas-sensing materials.