Fabrication of hierarchical Au@Fe2O3-SnO2 core-shell nanotubes with high n-butanol sensing performance

As a typical toxic and hazardous industrial gas, n-butanol poses a potential threat to production safety and human health. It is essential to develop advanced sensors for effectively and reliably detecting n-butanol gas. Herein, hierarchical Au@Fe2O3-SnO2 core -shell nanotubes were prepared and used as functional materials for nbutanol gas sensing. The as -synthesized composites exhibit tube morphology with nanostructures of inner alpha-Fe2O3 1D nanotubes and outer grown SnO2 films, and Au nanoparticles (NPs) anchored on the surfaces. Au@Fe2O3-SnO2 core -shell nanotubes present high response toward n-butanol compared with pure alpha-Fe2O3 and Fe2O3-SnO2, and the proportions of Sn and Au were further optimized. The Au2FeSn5 possesses the optimal gas sensing properties both in the relatively dry and humid atmospheres. At the optimum working temperature of 240 celcius (-25% RH, -22 celcius), Au2FeSn5 sensor presents high response of 45.0 toward 100 ppm n-butanol, fast response/recovery time of 10/5 s, excellent linearity in the concentration range of 0.02-1000 ppm, low theory limitation of detection (LOD) of 2.2 ppb and good reproducibility and stability. The possible sensing enhancement mechanism was proposed from the point of views of gas adsorption and electron transfer. The heterojunctions between two oxides and the sensitization of Au NPs could contribute to the sensitivity to n-butanol detection.