Engineering of in-plane SnS-SnO nanosheets heterostructures for enhanced HS sensing.

In-plane heterostructures has attracted considerable interest due to exceptional electron transport properties, high specific surface area, and abundant active sites. However, synthesis of in-plane SnS-SnO heterostructures are rarely reported, and the deep investigation of the fine structure on reactivity is of great significance. Here, we propose partial in-situ oxidation strategy to construct the in-plane SnS-SnO heterostructures and the surface properties, the ratio of two components can be finely tuned by precisely adjusting the treatment temperature. In particular, the SnS-SnO heterostructures formed after annealing of SnS nanosheets at 350 °C exhibits a unique electronic structure and surface properties due to rich grain boundaries, which exhibits excellent gas sensing performance to HS (R/R = 169.81 for 5 ppm HS at 160 °C, fast response and recovery dynamic (41/101 s), excellent reliability (σ = 0.01) and sensing stability (φ = 0.11 %)). Notably, the in-plane heterostructures endow the material with abundant grain boundaries and effectively regulates the electronic structure of the Sn p-orbital, which facilitate the formation of active oxygen species (O(ad)), thus contributing to the sensing performance. Our work provides a promising platform to design in-plane heterostructures for various advanced applications.