Fabrication of SnO2/CNTs formaldehyde gas sensor

Formaldehyde (CHOH) is an important chemical industrial material and organic solvent. Formaldehyde is a harmful gas. It strongly irritates human eyes and nose, and is a carcinogen. Semiconductor gas sensors are cheap to make and easy to use, and can convert the gas concentration directly to electrical signals. There were some reports on formaldehyde gas sensor using semiconductor materials, such as NiO, ZnO/ZnSnO₃ etc. Hybrids carbon nanotubes/SnO₂ gas sensor was used to detect N₂. Carbon nanotubes/WO₃ sensor detected NO₂ and CO. In this report, a formaldehyde gas sensor was fabricated by a composite of nanometer SnO₂ and functionalized multi-wall carbon nanotubes (MWCNTs). The sensitivity of the composite of SnO₂/MWCNTs to formaldehyde gas was much improved.