MoS ₂–NiO nanocomposite for H ₂S sensing at room temperature†

Abstract

The layered 2-D materials, such as molybdenum disulfide (MoS ₂), are among the most promising candidates for detecting H ₂S gas at very low concentrations. Herein, we have designed a series of novel nanocomposites consisting of MoS ₂ and NiO. These materials were synthesized via a simple hydrothermal method. The microstructure and morphology of nanocomposites were studied using different characterization techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). These nanocomposites were used as gas sensors, and the highest response (6.3) towards 10 ppm H ₂S was detected by the MNO-10 gas sensor among all the tested sensors. The response value ( R _g/ R _a) was almost three times that of pure NiO ( R _g/ R _a = 2). Besides, the MNO-10 sensor exposed good selectivity, short response/recovery time (50/20 s), long-term stability (28 days), reproducibility (6 cycles), and a low detection limit (2 ppm) towards H ₂S gas at RT. The excellent performance of MNO-10 may be attributed to some features of MoS ₂, such as a layered structure, higher BET surface area, higher active sites, and a synergistic effect between MoS ₂ and NiO. This simple fabrication sensor throws a novel idea for detecting H ₂S gas.

Abstract

The layered 2-D materials, such as molybdenum disulfide (MoS ₂), are among the most promising candidates for detecting H ₂S gas at very low concentrations.