LAUSR

In this work, the fabrication process and the gas sensing performance toward n-butanol of urchin-like Au decorated SnO2/Fe2O3 (Au at SnO2/Fe2O3 microspheres were presented in detail. The hierarchical SnO2/Fe2O3 structure was constructed by using Fe2O3 microspheres as a precursor and combining with in-suit growth of SnO2 micropillars on their surface. The well-designed hierarchical structures were further decorated with different amounts of Au nanoparticles (NPs). The comparative analysis of gas sensing results illustrated that the heterojunctions between SnO2 and Fe2O3 and the sensitization of Au NPs were achieved by modulating the loading amounts of Au NPs, which contributed to the sensing performance enhancement. The best sensing properties were obtained on Au1 at SnO2/Fe2O3 (Au NPs 1wt%)-based sensor, which exhibited high response of 175.4- to 100-ppm n-butanol [240 °C and $\sim $ 25% relative humidity (RH)], rapid response/recovery time (6/7 s), good linearity (0.02–0.5 and 1–1000 ppm), low limit of detection (LOD, 20 ppb), and optimum selectivity and superior stability (±3% at 100 ppm for 5 weeks).