Hydrogen peroxide is prepared by the action of $ C{{O}_{2}} $ on barium peroxide $ (Ba{{O}_{2}}) $ .
$\underset{\text{(Barium peroxide)}}{BaO_2} + CO_2 + H_2O \to \underset{\text{(Barium carbonate)}}{BaCO_3}$
$ + \underset{\text{(Hydrogen peroxide)}}{H_2O_2}$