In-situ construction of SnO2 nanolayer-SnS2 nanosheets heterostructures for enhanced NO2 sensing at room temperature and their DFT investigation

Traditional NO2 sensors based on metal oxide semiconductors suffer from high power consumption, creating a pressing demand for novel NO2 sensors operating at room temperature. Motivated by this, SnO2 nanolayer modified SnS2 nanosheets heterostructures were successfully prepared through an in-situ synthesis process by mildly annealing pure SnS2 nanosheets for NO2 detection at room temperature. The SnO2 oxidation nanolayer was formed on the SnS2 nanosheets with an average thickness of 14 nm. The optimal sensor based on the obtained heterostructures achieves a high response of 6.0-1 ppm NO2 at room temperature of 25 degrees C. The designed sensor also exhibits excellent repeatability, selectivity, and long-term stability. Furthermore, the density functional theory calculations proved that the presence of SnO2 nanolayer promoted NO2 adsorption capacity of SnS2 nanosheets, thereby enhancing the sensing performance. The extraordinary gas sensing performance was ascribed to enhanced specific surface area and n-n heterojunction built between the SnO2-SnS2 interface. The novel SnO2 nanolayer-SnS2 nanosheets heterostructures offer a promising candidate for high-performance room-temperature NO2 sensors.