Gas sensors based on SnS<sub>2</sub>/In<sub>2</sub>O<sub>3</sub> for high performance NO<sub>2</sub> detection at room temperature

NO₂ is a toxic gas that reacts with other organic compounds in the air, causing air pollution and posing a significant risk to humans. Therefore, a gas sensor is needed to detect NO₂. However, conventional NO₂ gas sensors are difficult to operate at room temperature (25℃). In this study, NO₂ gas sensing by SnS₂/In₂O₃ at room temperature (25℃) is reported. In₂O₃ quantum dots and SnS₂ nanosheets were prepared by the hot-injection and hydrothermal methods. By virtue of the unique two-dimensional structure of SnS₂, In₂O₃ was decorated on it, and the composite enhanced its sensing performance. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrate that the composites prepared by 52% In₂O₃ exhibit the best sensing response. The fabricated sensor shows a response of 26.6 to 1000 ppb NO₂, along with fast response and recovery times, respectively, at room temperature (25℃). Moreover, this sensor demonstrates excellent reproducibility and selectivity. The heterojunction structure increases the number of active sites and accelerates the gas transport, which promotes charge transfer and gas desorption to improve NO₂ gas sensing performance. This excellent sensing performance has a great application prospect in NO₂ detection.