Improved Gas-Sensing Properties of Hierarchical Porous Sno2 Microflowers Modified with AU Nanoparticles

Hierarchical Au-decorated SnO2 (Au@SnO2) microflowers with a porous structure were synthesized using a facile hydrothermal method, followed by calcination and modification processes. The hierarchical structure consisted of a large number of porous uniform nanosheets. The Au-decorated SnO2 microflowers sensor presents excellent gas-sensing properties for volatile organic compounds (VOCs). In particular, for the accurate and fast detection of formaldehyde, the 2%Au-decorated SnO2 microflowers sensors showed a strong sensing response (76.5) for formaldehyde (100 ppm), which was approximately three times higher than 28.2 observed for the pure porous SnO2 microflowers. The response/recovery times were 10 s and 16 s, respectively, which were shorter than those of pure SnO2 (12 s/25 s). The larger available specific surface area of favorable porous flower-like structure, high catalytic activity, and electron sensitization effect of Au NPs improved the gas-sensing performance. Furthermore, the catalytic activity of Au NPs was maximized because of the uniform distribution on the surface of each porous SnO2 nanosheet. The Au-decorated SnO2 microflowers sensors have great potential for the accurate, fast, and high sensing response detection of formaldehyde gas.