Selective methanol-sensing of SnS-supported ultrathin ZIF-8 nanocomposite with core-shell heterostructure

Abstract

Herein, a novel room-temperature methanol sensor was designed and fabricated by constructing a core-shell heterostructure composed of stannous sulfide (SnS) and zeolitic imidazolate framework-8 (ZIF-8). The core-shell morphology of the obtained SnS/ZIF-8 nanocomposite is characterized by tiny ZIF-8 nanocrystalline uniformly attached on the surface of SnS nanoflakes. During the synthesis, the SnS surface adsorbed more Zn ions by forming S-Zn coordination bonds, which not only induced the in-situ growth of ZIF-8, but also contributed to the formation of tight heterojunctions. Benefiting from the ultrathin sensing surface of ZIF-8 and the heterogeneous interface between SnS and ZIF-8, the electrical conductivity and adsorption active sites are significantly promoted, which is clarified by the combination of experiments and first-principles calculations. Notably, the SnS/ZIF-8 sensor reveals a high response of 68.65–10 ppm methanol at 25 °C, with a low limit of detection of 8.27 ppb. Moreover, it also demonstrates excellent selectivity for methanol against different VOCs and NO2 owing to the molecular sieving effect of ZIF-8. The present study paves the way for the design of two-dimensional sulfide/metal-organic frameworks (MOFs) heterogeneous architectures with practical gas-sensing performance.