Potassium Superoxide ($\ce{KO2}$) is used as an oxygen provider and carbon dioxide scrubber in life support systems $$\ce{2KO2 + H2O -> 2KOH + O2} \\ \ce{2KOH + CO2 -> K2CO3 + H2O}$$

I encountered a question that asked if Potassium superoxide can also serve as a scrubber for $\ce{CO}$. I thought of a reaction where $\ce{KO2}$ oxidized $\ce{CO}$ to $\ce{CO2}$ and the $\ce{CO2}$ was absorbed as previously mentioned $$\ce{2KO2 + 2CO -> K2O2 + 2CO2}$$ Another possible reaction would be reduction of $\ce{KO2}$ to $\ce{K2O}$ $$\ce{2KO2 + 3CO -> K2O + 3CO2}$$

I could not find these reactions or similar ones mentioned in any literature online. This article describes the working of $\ce{KO2}$ in detail but I could not find a mention of carbon monoxide in there.

Can $\ce{KO2}$ also be used to scrub $\ce{CO}$? If so, how?


2 Answers 2


As the other answer and comments imply, potassium superoxide is not a good reagent for absorbing carbon monoxide. Cuprous chloride solution works better, as in this study[1] where the salt is dissolved in an ammonia-bearing solution.


  1. R. V. Gholap and R. V. Chaudhari, "Absorption of carbon monoxide with reversible reaction in cuprous chloride solutions", Ind. Eng. Chem. Res. 27, 11, 2105–2110 (1988).

No, the reactions involving KO2 do not directly react as you indicated, although there is a claimed reaction producing a curious analog to H2O2 with a potassium atom taking the place of one of the hydrogen atoms from the action potassium superoxide with water (water vapor):

$\ce{2 KO2 + H2O -> KOH + KHO2 + O2}$

But, still no reaction of CO with KHO2 forming CO2 expected.

Interestingly, in the presence of the hydroxyl radical, however, per this source, Eq (15), to quote:

$\ce{CO + .OH -> CO2 + .H}$

but maybe occurring only at low temperatures.

So, given a visible light, or UV photocatalyst like TiO2, in presence of water and carbon monoxide, at the appropriate temperature, perhaps a slow limited conversion of CO to CO2 is, after all, theoretically possible, but decidedly not practical.

Note: CO will burn in air/oxygen forming CO2:

$\ce{2 CO + O2 -> 2 CO2}$

Reference: See, for example, this ebook.


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