Electrode Influence on Gas Sensor Response

Korotcenkov, Handbook of Gas Sensor Materials Properties, Advantages and Shortcomings for Applications Volume 1 Conventional Approaches, Integrated Analytical Systems, 

Bertrand et al. (2006, 2007) studied SnO sensors with Au and Pt electrodes using DC conductance and DRIFTS measurements and demonstrated that the different nature of the electrodes changes the chemistry involved in CO sensing. Different distribution between carbonates and carboxylates, which are the reaction intermediates when CO is converted to CO, were identified. 

That the metal-semiconductor junction may be the main gas-sensing element responsible for the observed sensor response was confirmed by Tamaki et al. (2005). In this study, the effect of gap size between Au electrodes on the sensor response to dilute NO was investigated (see Fig. 9.2). Gap sizes in WO3 microsensors were varied from 0.1 to 1.5 mm. It was found that the response to dilute NO was unchanged for gap sizes larger than 0.8 mm, whereas below 0.8 mm the sensor response 

Response to humidity was also affected by the electrode material. Ylinampa et al. (1993) and Capone et al. (2001) established that the influence of water on the CO response of SnO -based sensors is greater in the case of Au contacts and lower in the case of Pt contacts. 

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