Sensing mechanism of Ag/α-MoO₃ nanobelts for H₂S gas sensor

Sensing mechanism is still a big problem in the field of gas sensor. In-depth study of the sensing mechanism can provide better ideas for the design of sensing materials, and it is also more conducive to the improvement in gas-sensing performance. In this work, Ag/α-MoO₃ material was obtained by loading Ag in α-MoO₃ nanobelts prepared by hydrothermal method. The material was characterized by field electron scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Comparing the gas sensing properties of α-MoO₃ and Ag/α-MoO₃, it is found that Ag effectively improves the selectivity of the material to H₂S at 133 °C. The response of the 5 wt% Ag/α-MoO₃ sensor to 100 × 10⁻⁶ hydrogen sulfide (H₂S) is 225 and the detection limit is 100 × 10⁻⁹. The sensing mechanism was verified by gas chromatography and mass spectrometer (GC–MS), XPS and Fourier transform infrared spectroscopy (FTIR).