MoS₂ Nanoflowers Decorated with Au Nanoparticles for Visible-Light-Enhanced Gas Sensing

Highly sensitive and selective detection of trace nitrogen dioxide (NO2) in a complex outdoor air environment is an urgent need to guarantee human health and a beautiful environment. The effective combination of heterostructure and light irradiation is an important strategy to achieve high-performances gas sensors. However, the effect of light irradiation on gas-sensitive properties of heterostructure materials is not yet clear, and it is urgent to clarify the relationship between light irradiation and heterostructure for gas-sensing materials. Herein, a 530 nm-light-assisted Au–MoS2 gas sensor with a low detection limit as well as robust antihumidity interference ability is developed through introducing the localized surface plasmon resonance (LSPR) effect of Au nanoparticles (NPs). Under 530 nm light illumination, a Au–MoS2 gas sensor can achieve limit detection of NO2 as low as 10 ppb without operating temperature along with robust antihumidity ability. The optical simulation and experimental results show that the modification of MoS2 by Au NPs (diameter: 30 nm) combined with the matching light-assisted (530 nm) gas detection mode can make MoS2 fully absorb visible light and effectively improve the extinction cross section by taking full advantage of the LSPR effect, which is the primary reason for the enhanced performances of a MoS2-based gas sensor. This work provides theoretical and experimental guidance for gas sensors to effectively enhance the ability of gas detection by means of the light-assisted mode at room temperature, which opens up a unique approach to design high-performance gas sensors for trace-level gas detection.