Room temperature ethanol gas-sensing properties based on Ag-doped MoSe2 nanoflowers: experimental and DFT investigation

Abstract

An Ag-doped MoSe₂ nanomaterial-based sensor was fabricated for ppb-level ethanol sensing at room temperature. The MoSe₂ and Ag-modified MoSe₂ nanoflowers were synthesized by a hydrothermal method, which exhibited high purity and crystallinity. Some characterization techniques such as SEM, TEM, XRD and XPS were employed to comprehensively analyze the micromorphology and microstructure of the Ag–MoSe₂ sample. The Ag-modified MoSe₂ nanomaterial was composed of nanoflowers assembled with many nanosheets. The gas-sensing results confirmed that compared with pristine MoSe₂, the Ag-modified MoSe₂ based sensor exhibited a low detection limit (10 ppb) and good response/recovery characteristics towards ethanol at room temperature, which could be used for alcohol testing on drinkers. To further verify and explain the sensing mechanism, pristine and Ag-doped MoSe₂ adsorption configurations were simulated via the first-principles study based on density functional theory (DFT). Interestingly, the Ag–MoSe₂ system exhibited excellent ethanol sensing performance compared with the pristine MoSe₂ system, which was consistent with the experimental results. This work presents the combination of experimental and DFT simulation to substantiate that Ag-doped MoSe₂ nanoflowers are promising candidates for low-concentration ethanol detection at room temperature.