Visible light enhanced NO2 sensing performance of Au nanoparticles modified SnS2 hierarchical structure at room temperature

High-performance NO2 gas sensor at room temperature is vital in daily life. Herein, the performance of SnS2 hierarchical structure modified by Au nanoparticles was explored as a NO2 sensing material at room temperature. The samples were synthesized by solvothermal method and subsequent in-situ reduction method which could be confirmed by the analysis results of X-ray powder diffractometer (XRD), field-emission scanning electronic microscope (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectra (XPS). Through a series of gas sensing measurements, the sensor based on Au-SnS2 possesses outstanding NO2 sensing properties under visible light at room temperature, including high response at trace concentration (14.24/5 ppm), excellent response/recovery time (29/148 s), low detection limit (36 ppb), satisfactory selectivity and repeatability. Combined with the first-principles calculations, the enhanced sensing performance can be contributed to the modification of Au with rich charge transfer (−0.5153 e) and the local surface plasmon resonance (LSPR) between Au and visible light with the enhanced optical absorption capacity and carrier density of the material. This work proffers opportunities for real-time NO2 detection in daily life.