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CO2 To Ethanol In One Step With Cheap Catalyst (sciencedaily.com)
Reader networkBoy writes: Boffins at ORNL (Department of Energy's Oak Ridge National Laboratory) have discovered a simple and cheap catalyst that can take CO2 (Carbon Dioxide) dissolved in solution with water and at room temperature convert it to ethanol with 60%+ yields. They envision it as a way to store surplus power from green energy plants and then burning it to fill in lulls in supply.From the report:The team used a catalyst made of carbon, copper and nitrogen and applied voltage to trigger a complicated chemical reaction that essentially reverses the combustion process. With the help of the nanotechnology-based catalyst which contains multiple reaction sites, the solution of carbon dioxide dissolved in water turned into ethanol with a yield of 63 percent. Typically, this type of electrochemical reaction results in a mix of several different products in small amounts. "We're taking carbon dioxide, a waste product of combustion, and we're pushing that combustion reaction backwards with very high selectivity to a useful fuel," Rondinone said. "Ethanol was a surprise -- it's extremely difficult to go straight from carbon dioxide to ethanol with a single catalyst."
It's a flavor of an obscure Germanic language spoken by a large portion of the civilized people in this place called 'America.' You may have heard of it. We're renowned for our trucks and our elevators, as well for as our scientists and engineers. No boffins though.
As I read it, TFA _does_ give a clue as to efficiency.
60% of the electrons are used for producing ethanol.
Equilibrium potential for the ethanol reaction is 84 mV.
The total voltage that is used is 1.2V, which is 14 times as high.
That means that only 7% of the voltage is used effectively.
This gives a total energy of a little over 4%.
In the conclusion, this is mentioned as "The overpotential (which might be lowered with the proper electrolyte, and by separating the hydrogen production to another catalyst) probably precludes economic viability for this catalyst"
So, they don't (dare to) mention efficiency directly, but data is presented by which it can be calculated.