Graphene oxide/SnO2 Nanocomposite as Sensing Material for Breathalyzers: Selective Detection of Ethanol in the presence of Automotive CO and Hydrocarbons Emissions

SnO2 was ultrasonically deposited-precipitated in the presence of different amounts of graphene oxide (GO) prepared by the modified Hummers' method. The resulting nanocomposites were used as the sensing material for detection of 1000 ppm CO and VOCs including ethanol, acetone and toluene and CH4 in a temperature range of 150-300°C. The nanocomposites were characterized by Raman spectroscopy, XRD, BET surface area measurement, FT-IR and SEM methods. It seems that SnO2 layers were deposited on the GO surface and incorporated into the matrix. This results in 47% increase in the nanocomposite BET surface area. Addition of 0.1 wt% GO to SnO2 increases the response to CO by about 6 times, at 300°C. As an optimum amount of 0.05 wt% GO is included in the SnO2, up to 2 fold enhancement in response to ethanol and toluene is observed. At 250oC, the highest response to ethanol is obtained, which is 120, 114, 1400 and 15 times larger than the responses to CO, toluene, methane and acetone, respectively, making the sensors quite selective to ethanol. Furthermore, this sensor exhibited good response in the low concentration of ethanol.