In the article they seem to be concerned that the atmosphere in the Starship is highly flammable, isn’t there a way to recycle CO2 into O2 ? instead of pushing

In the article they seem to be concerned that the atmosphere in the Starship is highly flammable, isn’t there a way to recycle CO2 into O2 ? instead of pushing a mix highly concentrated in O2. Perhaps we could avoid a catastrophe like there was during 60s space trainings ?