Synthesis of tin dioxide (SnO2) hollow nanospheres and its ethanol-sensing performance augmented by gold nanoparticle decoration

Herein, we report the fabrication of ethanol sensors with superior performance using gold (Au) nanoparticles decorated SnO2 hollow nanospheres (Au-SnO2 HNS). The SnO2 hollow nanospheres (SnO2 HNS) were synthesized by a hydrothermal method using carbon nanospheres as a sacrificial template. To improve their ethanol-sensing performance, Au nanoparticles were decorated on their surfaces. Morphological characterization by scanning electron microscopy and transmission electron microscopy indicates that the diameter of the SnO2 HNS and Au-SnO2 HNS ranged from 150 to 250 nm, and the wall thickness was 10 nm. The diameter of the Au nanoparticles on the surface of the hollow nanospheres ranged from 3 to 5 nm. After Au nanoparticle decoration, the ethanol-sensing response of SnO2 HNS improved 2.7 times when exposed to 100 ppm ethanol gas measured in 250 °C. Furthermore, the sensing response of Au-SnO2 HNS-based sensors presents a selective sensing response towards ethanol gas compared to other volatile organic compound (VOC) gases. These improved sensing properties originate from the optimized morphologies of the sensing materials and the catalytic effect of the Au nanoparticles.