A dynamic response model for the WO3-based ozone sensors

In this paper, a dynamic model based on the Wolkenstein adsorption theory is developed for temperatures equal to or less than 250 °C and non-dissociative adsorption. We assumed that the ozone detection mechanism of WO3-based gas sensors in dry air is essentially due to adsorption of species O2, O2−, O and O− at the surface of the grains. The simulation results are compared to the experimental ones. The correlation between simulated and experimental results is rather good. The model is then extended to the dissociative adsorption and higher temperatures. At temperature higher than 300 °C, an increase in the recovery time appears on experimental results and cannot be explained by a simple adsorption/desorption mechanism.