Edge-enriched SnS₂ nanosheets on graphene for chemiresistive room temperature NH₃ sensors

Transition metal dichalcogenides (TMDs) with a larger surface area, abundant surface defect, and controlled electrical performance are promising in field of gas sensor. While, their drawbacks are low sensitivity, sluggish recovery kinetics, and poor selectivity. Herein, graphene is functionalized with SnS₂ nanosheets by a hydrothermal process. Compared to pure SnS₂ and graphene, the room-temperature response to 500 ppm NH₃ is about 91.32 %, which is increased by 1700 % and 63.63 %, respectively. With increase of temperature and humidity, the baseline resistance and NH₃-sensing response decreases strongly. The effect of temperature and humidity on resistance change of composites is high and the desired NH₃-sensing response of composites may not yet be reached due to its high sensitivity towards humidity and temperature fluctuations. Additionally, the room-temperature response to 100 ppm NO₂ is only about 17.83 %, which is much smaller than that of NH₃ (62.36 %) and the resistance couldn't recovery to initial value, behaving the poor recovery performance for NO₂. The Density-functional theory calculations reveal that the stronger NH₃ adsorption ability of SnS₂, higher carrier mobility of graphene, and more effective charge transfer at p-n heterointerface contribute to the enhancement. © 2025 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.