Comparative Study of VOC Sensors Based on Ruthenated MWCNT/SnO2 Nanocomposites

Thick-film VOCs sensors based on ruthenated multi-walled carbon nanotubes coated with tin-dioxide nanoparticles nanocomposite structures (MWCNTs/SnO₂) are prepared using three methods: hydrothermal synthesis, sol–gel technique and their combined process. Properties prepared nanocomposite powders are characterized by TEM and SEM techniques. It is shown that the optimal conditions for applications as acetone, toluene, ethanol and methanol vapors sensors in view of high response and selectivity relative to each other depend on choice of material synthesis method, mass ratio of the nanocomposite components and selected operating temperature. MWCNTs/SnO₂ sensor structures having the mass ratio of the components 1:4 and 1:24 exhibit selective sensitivity to acetone and toluene vapors at 150^oC operating temperature, respectively. The samples with 1:200 mass ratio of the nanocomposite components show the selective and response to acetone vapor exposure in the range of 200-250^oC operating temperatures. The high sensitivity to ethanol and methanol vapors at 200^oC operating temperature was revealed for the sensor structures made by all three proposed methods with the 1:8, 1:24, 1:50 and 1:66 ratio of the components.

Keywords: MWCNTs/SnO₂, VOCs, sensor acetone, toluene, ethanol, methanol