# How does the MG811 sensor work?

The MG811 is an electrochemical sensor that measures $\ce{CO2}$. I think is something like a redox reaction but i don't understant how it produces $\ce{e-}$ so i can read them and get the $\ce{CO2}$ concentration.

I copy you the reaction that makes the sensor measures

When the sensor exposed to $\ce{CO2}$，the following electrodes reaction occurs：

Cathodic reaction: $\ce{2Li+ + CO2 + 1/2O2 + 2e- -> Li2CO3}$

Anodic reaction：$\ce{2Na+ + 1/2O2 + 2e- -> Na2O}$

Overall chemical reaction：$\ce{Li2CO3 + 2Na+ -> Na2O + 2Li+ + CO2}$

The datasheet says that it workings adopting the electrolyte cell Principle and that it's composed by the following cells:

Air，$\ce{Au}$|NASICON|| carbonate|$\ce{Au}$, air，$\ce{CO2}$

I need you to explain me how actually the sensor is working and with which material are made the electrodes.

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