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Fuel for climate protection?

Klaus Esterluss
October 20, 2016

American scientists have stumbled upon a cheap and easy way to convert CO2 into ethanol. Yes, the stuff that can also be used to fuel your car.

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Image: picture alliance/dpa

"We discovered somewhat by accident that this material worked," says Adam Rondinone. Together with his colleagues, the scientist made a discovery that could put the greenhouse gas carbon dioxide to good use.

What the scientists did, in principle, is reverse the combustion process that produces carbon dioxide. The end product of the experiment at the US Department of Energy's Oak Ridge National Laboratory they produced ethanol. And this fuel, in turn, could not only power cars but also help to store energy.

In the beginning, Rondinone and his colleagues had planned a series of experiments.

"We were trying to study the first step of a proposed reaction when we realized that the catalyst was doing the entire reaction on its own," Rondinone said in a press release on the results of the experiment.

There were various reasons for the surprisingly quick results. For one, the researchers used simple, relatively cheap materials, in this case copper, carbon and nitrogen. Another aspect is the use of nanotechnology. "By using common materials but arranging them with nanotechnology, we figured out how to limit the side reactions and end up with the one thing that we want," said Rondinone.

Reversed combustion

For their catalyst, he and his colleagues placed tiny copper particles on microscopically small carbon tips. The result was a prickly surface, which clearly eased the process, because once voltage was applied, the resulting effects were very focused."They are like 50-nanometer lightning rods that concentrate electrochemical reactivity at the tip of the spike," said Rondinone.

Once energized, the catalyst reversed the combustion process that produces carbon dioxide and the scientists obtained ethanol with a yield of 63 percent, which was also surprisingly pure. Usually, similar electrochemical processes yield several end products so the amount of each individual chemical compound that can be recovered is much smaller.

Now Rondinone and his colleagues hope the results of their experiment can be applied to larger-scale processes. Because both, the effort and costs required are low, the concept could also be used for temporary storage of energy from wind or solar power plants. According to the researchers, excess energy could be stored as ethanol and later used when energy supply gaps arise.

An even more obvious option is the use as fuel. The ethanol obtained in the experiment could be used as fuel in today's road vehicles and even some aircraft. Normally, the fuel additive is a biofuel derived from plants grown exclusively for this purpose. this process often contributes significantly more to climate change than it actually prevents it.

The task for the scientists around Adam Rondinone is now to optimize the process and to prove that they have actually found a way to give climate-destroying carbon dioxide a climate-friendly face.