Modeling Interactions of Oxygen with the Zirconia Sensor

2 MODELING INTERACTIONS OF OXYGEN WITH THE ZIRCONIA SENSOR 

FIGURE 2.3 Schematic presentation of the interaction of the solid electrolyte oxygen sensor with gas environment 1-6 stages of interaction. (From Zhniykov, S., Mathematical model of electrochemical gas sensors with distributed temporal and spatial parameters and its transformation to models of the real YSZ-based sensors. Ionics 12 (2006) 135-148. With kind permission of Springer Science and Business Media.) 

Moreover, the oxygen ions can subdissociate to subions O, which can diffuse on the metal-electrolyte and gas-electrolyte boundaries toward the gas-SE-YSZ interface. Stage 3 is the electrochemical reaction of oxygen (Oj + — 20 ), which initiates 

In the case of the YSZ-based oxygen sensor with the Me-MeO RE, the electrochemical reactions take place at different kinetic rates on the dissimilar electrodes. On Stage 1, the dependence of the concentrations of physically adsorbed Nq2 f molecules on the partial pressure Pq2 of the measuring gas can be determined. For Stage 1, the following assumptions should be taken into account  

In our case, the dissociative form of adsorption dominates for the oxygen sensor working at temperatures of 700-900°C, and consequently the adsorption isotherm differs from the linear Langmuir adsorption isotherm [34]. 

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