Researchers at the US Department of Energy’s Oak Ridge National Laboratory (ORNL) in Tennessee have inadvertently discovered a way to turn carbon dioxide into ethanol, which can be used as fuel. This new method could be a key to removing carbon from the atmosphere to limit the effects of climate change, a step which experts have increasingly said will be necessary to avert catastrophic temperature increases. Until now, ideas for accomplishing this have focused on capturing and storing carbon, a method that has proved too costly to implement on a large scale.
The ORNL team were attempting to discover a series of chemical reactions to turn carbon dioxide into fuel, when they found that the first step, of what they expected to be an extensive process, created ethanol that can be used to power generators and vehicles. The team used copper and carbon “nanospikes” on a silicon surface, which along with voltage, was added to carbon dioxide to create ethanol. The process is essentially a reversal of the combustion process. The use of nanotechnology allowed the reactions to be precise, creating few contaminants and yielding usable ethanol. Otherwise, an electrochemical reaction of this nature would result in smaller yields of several different chemicals.
“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 Adam Rondinone, the lead author of the study, published in the journal ChemistrySelect.
“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. Ethanol was a surprise — it’s extremely difficult to go straight from carbon dioxide to ethanol with a single catalyst,” Rondinone continued.
This process would be more affordable, efficient, and scalable to an industrial level than other solutions for dealing with carbon emissions. Owing to the fact that it works at room temperature, energy cost is kept relatively low. The process also relies on low-cost materials, allowing it to be scaled up for broader use. The scientists say it could be used to balance and supplement the use of other renewable energy sources.
According to Rondinone, “A process like this would allow you to consume extra electricity when it’s available to make and store as ethanol, this could help to balance a grid supplied by intermittent renewable sources.”