The enhanced gas sensing characteristics of La₂O ₃-Doped SnO₂by the addition of multi wall carbon nanotubes

A La-doped SnO₂, (La-SnO₂) nano sol solution containing multi-wall carbon nanotubes (MWCNTs) was prepared by hydrothermal reaction and the gas sensing characteristics of the La-SnO₂/MWCNT composite sensors were investigated at various heat treatment temperatures (HTTs). The MWCNTs were unaffected, partially decomposed, and completely decomposed by the heat treatment at 500, 600, and 700 °C in air, respectively. However, regardless of the HTT variation, the gas responses to C₂H₆OH at 400 °C were increased 1.4-2.5 times by the addition of 0.1 wt% MWCNTs and the sensors showed selective detection to C ₂H₅OH. The mechanisms for the enhancement of gas response are discussed in relation to the decomposition of MWCNTs and its consequent effect on the gas sensing reaction.