Influence of heterogeneous reaction rate on response kinetics of metal oxide gas sensors: application to the recognition of an odour

摘要

The resistance response to a steep change in composition of the atmosphere is studied in polycrystalline thin films of tin and indium oxides. Based on common understanding that the gas is adsorbed on the surfaces prior to the chemical reaction, the phenomenological relationship containing the characteristics of the elementary steps of the reaction is deduced for the transient response. To describe the experimental results, some phenomenological parameters are introduced and their dependencies on the steps of the reaction are analysed. The limits and accuracy of such approximation is determined. The original method based on the analysis of the transients of the sensor array is proposed for graphical visualisation of the transients of the response to odours. The graphical plots were applied for recognition of the quality of chicken meat including the infection with bacteria.