Ppb-Level Hydrogen Sulfide Gas Sensor Based on the Nanocomposite of MoS(2) Octahedron/ZnO-Zn(2)SnO(4) Nanoparticles

Hydrogen sulfide (H(2)S) detection is extremely necessary due to its hazardous nature. Thus, the design of novel sensors to detect H(2)S gas at low temperatures is highly desirable. In this study, a series of nanocomposites based on MoS(2) octahedrons and ZnO-Zn(2)SnO(4) nanoparticles were synthesized through the hydrothermal method. Various characterizations such as X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectrum (XPS) have been used to verify the crystal phase, morphology and composition of synthesized nanocomposites. Three gas sensors based on the nanocomposites of pure ZnO-Zn(2)SnO(4) (MS-ZNO-0), 5 wt% MoS(2)-ZnO-Zn(2)SnO(4) (MS-ZNO-5) and 10 wt% MoS(2)-ZnO-Zn(2)SnO(4) (MS-ZNO-10) were fabricated to check the gas sensing properties of various volatile organic compounds (VOCs). It showed that the gas sensor of (MS-ZNO-5) displayed the highest response of 4 to 2 ppm H(2)S and fewer responses to all other tested gases at 30 °C. The sensor of MS-ZNO-5 also displayed humble selectivity (1.6), good stability (35 days), promising reproducibility (5 cycles), rapid response/recovery times (10 s/6 s), a limit of detection (LOD) of 0.05 ppm H(2)S (R(a)/R(g) = 1.8) and an almost linear relationship between H(2)S concentration and response. Several elements such as the structure of MoS(2), higher BET-specific surface area, n-n junction and improvement in oxygen species corresponded to improving response.