Thermodynamic study of alcohol on SnO2(100)-based gas nano-sensor

Alcohol dehydrogenation and condensation reactions are involved in chain growth pathways of SnO2. These pathways lead to the formation of acetaldehyde and other products with high selectivity. It is recognised that together with the atmospheric oxygen, the presence of humidity greatly influences gas detection. Accordingly, it is important to understand the role of alcohol vapours in the sensing mechanism. Interaction between alcohol molecules and SnO2 is investigated using MNDO method by semi-empirical calculations. We study the structural, total energy, thermodynamic properties of absorption of CH3OH and C2H5OH on SnO2 at 298 K. When exposed to ethanol, the SnO2-based sensors showed oxidation products consisting of acetaldehyde, ethyl acetate and CH4 + CO. All the geometry optimisation structures were carried out using the Gaussian program package. Density functional theory optimised intermediates and transient states. The results show a sensitivity enhancement in resistance and capacitance when ethanol ...