Loading regulation of gold nanoparticles on self-assembled 3D MoO3 hierarchical structure for high triethylamine sensing

Au@MoO3 nanocomposites for effectively detecting triethylamine (TEA) have been successfully synthesized via facile hydrothermal method by regulating the loading paths of Au nanoparticles (NPs). Due to the difference in loading effect, the introduction sequence of Au is adjusted to investigate their phase composition, micro-structure and gas sensitivity with the techniques of XRD, Raman, FT-IR, UV-Vis, SEM, TEM, XPS and BET. 3D hierarchical structure assembled by 200–500 nm nanosheets is formed with relatively large specific surface area. The typical Au@MoO3-H-C sensor loaded with more Au NPs (size of 10–20 nm) has the higher response of 106.6 to 25 ppm TEA with the lower detection limit of 0.1 ppm and the relatively short response/recovery times of 14/47 s at 240°C. Compared with other interfering vapors (including acetone, formaldehyde, isopropanol, glycol, ethanol, n-octane and ethylenediamine), the sensor has significant selectivity and anti-interference to TEA, as well as the reliable repeatability and stability. Its augmented TEA-sensing may be attributed to the synergies between sensitization effect of Au NPs and hierarchical structure with high active sites, which deliver great potential for the wide application of metal oxide gas sensor.