1 research outputs found
Volatile Organic Compound Sensing with WO<sub>3</sub>‑Based Gas Sensors: Surface Chemistry Basics
The sensing properties of WO3-based gas sensors
were
evaluated at an operating temperature of 150 °C in the presence
of different volatile organic compounds (VOCs). Simultaneously to
the sensing tests, operando diffuse-reflectance infrared
Fourier transform spectra were acquired. Remarkably, no CO2 generation was observed under gas exposure for any of the target
VOCs. Catalytic combustion properties of the WO3 toward
acetone and ethanol at temperatures from 150 to 400 °C, both
in dry and humid atmospheres, were additionally performed. Such measurements
confirmed that no combustion occurred for ethanol (up to at least
300 °C) while it became detectable for acetone only starting
from 250 °C. The reaction products are acetaldehyde and acetate
in the case of ethanol exposure and acetate and formate in the case
of acetone exposure. The oxidation catalytic effect of WO3 was confirmed for both toluene, where benzaldehyde and benzoate
modes were observed, and acetylene (where acetaldehyde and ethenol
were detected). The systematic absence of CO2 as a product
and the identification of oxidized species are the basis of the proposed
reaction mechanisms