How to produce oxygen out of Venusian atmosphere's carbon dioxide?

Question

What are the possible methods of in-situ extraction of oxygen from the atmosphere of Venus, which is mostly carbon dioxide?

Answer 1

Some of your options are:

• Electrolysis of the atmosphere (see e.g. how MOXIE will do it on Mars), for which you will need a source of electricity, a catalyst (e.g. zirconia), and which produces carbon monoxide and oxygen: $$\require{mhchem}\ce{2 CO2} + \text{energy} → \ce{2 CO + O2}$$ Carbon monoxide can be further reduced into elemental carbon and oxygen by the same process, but that requires more input energy to break the carbon-oxygen trivalent bond: $$\ce{2 CO + energy → 2C + O2}$$

• Photosynthesis, for which you will need water, light and photosynthesizing plant life which might require additional nutrients, or artificial photosynthesis technology: $$\ce{CO2 + 2 H2O + photons → CH2O + O2}$$

• Bosch reaction followed by electrolysis of water, which requires input hydrogen, likely some catalyst (e.g. iron), and high reaction temperature (450 to 600 °C), producing molecular oxygen, elemental carbon, and molecular hydrogen that you can recycle back into your oxygen production: $$\ce{CO2 + 2 H2 → C + 2 H2O}$$ $$\ce{2 H2O + energy → O2 + 2 H2}$$

If you really have to do this on Venus, be prepared to deal with sulfuric acid ($\ce{H2SO4}$) and hydrogen sulfide ($\ce{H2S}$), because they're pretty much the only viable sources of hydrogen. You will likely need also other materials to sustain your endeavors on Venus, so see some suggestions which ones to look for and where e.g. in this answer.