In what’s been dubbed a “twist of fate” discovery, scientists at the U.S. Oak Ridge National Laboratory have created a catalyst capable of turning carbon dioxide into ethanol.
It’s a process that could provide a viable long-term storage solution for sources of renewable energy such as wind and solar power.
The ORNL team used a catalyst made from nanoparticles of copper, carbon and nitrogen in combination with an electrochemical reaction to convert a solution of carbon dioxide – a primary greenhouse gas – and water into ethanol; with a yield of 63 percent.
The result came as a surprise to researcher Adam Rondinone.
“We discovered somewhat by accident that this material worked,” said Rondinone, lead author of the team’s study published in the journal ChemistrySelect. “We were trying to study the first step of a proposed reaction when we realised that the catalyst was doing the entire reaction on its own.”
Using a single catalyst to essentially reverse the combustion cycle usually requires rare and expensive metals like platinum, but the ORNL’s catalyst is made from cheap and abundant, yet highly nanostructured copper particles embedded in carbon spikes.
“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,” Rondinone said.
The scientists say the “spiky” texture of the catalyst provided more reactive surface area to drive the carbon dioxide-to-ethanol conversion process.
“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.”
The researchers believe the low-cost materials involved in the technique plus the ability to operate at room temperatures means the process can now be scaled up to industrial applications, such as storing surplus electricity from variable sources such as solar and wind.
“A process like this would allow you to consume extra electricity when it’s available to make and store as ethanol,” Rondinone said. “This could help to balance a grid supplied by intermittent renewable sources.”
