Scientists Accidentally Discover Efficient Process to Turn CO2 Into Ethanol

[paulkienitz]

15. ethanol is a surprising outcome

As near as I can guess how it might work, it could turn two carbon dioxides into two carbon monoxides plus an oxygen molecule, and if you stick those COs together and decorate with hydrogen (thereby producing more oxygen, if you get the hydrogen from water)... well, it's not ethanol, it's ethylene glycol -- antifreeze. There must be something about the process that favors an asymmetrical alcohol molecule over the glycol -- something that involves losing yet more oxygen. Even if there's a bias, though, it's hard to see how it couldn't be producing a significant fraction of either ethylene glycol, ethane, or both, as producing ethanol involves splitting the difference between those.

They are downplaying the electric part of the process by noting that it only takes 1.2 volts... but if you want to produce in quantity, I bet the current has to be huge. You have to put in at least the energy you'd get by burning the fuel, so that's a lot of electricity. Given that it uses low voltage DC the ideal power supply would probably be solar panels. The yield per acre would not be anything terrific.