Synthesis of Au Nanoparticles Functionalized 1D α-MoO3 Nanobelts and Their Gas Sensing Properties

A novel sensor material of Au nanoparticles (NPs) functionalized 1D alpha-MoO3 nanobelts (NBs) was fabricated by a facile lysine-assisted approach. The obtained Au/alpha-MoO3 product was characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy dispersive X-ray (EDX), and X-ray photoelectron spectra (XPS). Then, in order to investigate the gas sensing performances of our samples, a comparative gas sensing study was carried out on both the alpha-MoO3 NBs before and after Au NPs decoration by using ethanol vapor as the molecular probe. The results turned out that, after the functionalization of Au NPs, the sensor exhibited improved gas-sensing characteristics than the pure alpha-MoO3, such as response and recovery time, optimal operating temperature (OT) and excellent selectivity. Take for example 200 ppm of ethanol, the response/recovery times were 34 s/43 s and 5.7 s/10.5 s, respectively, while the optimal operating temperature (OT) was lower to 200 degrees C rather than 250 degrees C. Besides, the functionalized sensor showed a higher response to ethanol at 200 degrees C, and response was 1.6 times higher than the pure MoO3. The mechanism of such improved sensing properties was interpreted, which might be attributed to the spillover effect of Au NPs and the electronic metal-support interaction.