Influence of hierarchical nanostructures on the gas sensing properties of SnO2 biomorphic films

SnO2 hierarchical films with interwoven tubular structures assembled by nanocrystallites have been achieved through a sol–gel approach combined with calcination treatment and involving eggshell membrane as a template. The gas-sensing property and the sensing mechanism have been studied from the sensor responses to ethanol, formaldehyde, liquefied petroleum gas, gasoline, and H2S species, based on the investigation of the crystallite size, specific surface area, and Raman surface vibration modes. It is investigated that as-synthesized SnO2 as a gas sensor has significant advantages attributable to the small nanocrystallite units and hierarchical assembly, which are mainly responsible for the surface activity of the SnO2 films and further influence on the gas sensing properties.