Hydrothermal synthesis of Au@SnO2 hierarchical hollow microspheres for ethanol detection

•The hierarchical structure of SnO2 was synthesized by structure directing agent and hard template.•The sensor has a high response to ethanol and the low detection limit (LOD) is 6.65 ppb to ethanol at 240 °C.•Au@SnO2 hierarchical hollow microspheres can be an excellent candidate in ethanol detecting. In this paper, Au@SnO2 hierarchical hollow microspheres were synthesized using template-assisted hydrothermal method, and utilized in ethanol detection. In the prepare process, Au@SnO2 hollow microspheres were synthesized by removing C-sphere template in high temperature annealing, before that, Au was embedded in the C-sphere template by regulating the amount of chloroauric acid. The surface morphological characterization and element content analysis of the samples were used to demonstrate structure and chemical state of all samples. The systematic gas sensing characterizations was carried out to learn the sensing performance of every sensor. The sensitivity (23.93) was three times higher than the pure SnO2 based sensor (8.48), and the optimal operating temperature was reduced to 240 °C. It presented excellent response/recovery time (4/48 s) additionally. These phenomenons indicated that Au increased the capacity of chemisorbed oxygen on the surface of sensitive materials (catalytic characteristic). In addition, the hierarchical structure of Au@SnO2 hollow microspheres also provided more active sites for sensing ethanol (structural characteristic). All the results showed that Au@SnO2 hierarchical hollow microspheres has a wide range potential application for ethanol detection.