Engineering of in-plane SnS₂-SnO₂ nanosheets heterostructures for enhanced H₂S 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 SnS₂-SnO₂ 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 SnS₂-SnO₂ heterostructures and the surface properties, the ratio of two components can be finely tuned by precisely adjusting the treatment temperature. In particular, the SnS₂-SnO₂ heterostructures formed after annealing of SnS₂ nanosheets at 350 °C exhibits a unique electronic structure and surface properties due to rich grain boundaries, which exhibits excellent gas sensing performance to H₂S (R_a/R_g = 169.81 for 5 ppm H₂S 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.