A team of scientists at the US Department of Energy’s Oak Ridge National Laboratory (ORNL) has developed a new electrochemical process, which converts carbon dioxide into ethanol.

The team at the ORNL applied a voltage to a combination of carbon, copper, and nitrogen to trigger a complex chemical reaction, which reversed combustion. By using a nanotechnology-based catalyst with multiple reaction sites in this way, a dissolved carbon dioxide solution turned into ethanol with a yield of 63%.

Study lead author Adam Rondinone said: “We discovered somewhat by accident that this material worked.

“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.

“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.”

The catalyst’s uniqueness lies in its nanoscale structure, which consists of copper nanoparticles embedded in carbon spikes. The nano-texturing approach eliminates the use of expensive or rare metals such as platinum, which limits the economic viability of many catalysts.

Rondinone said: “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."

Initial analysis indicates that the spiky textured surface of the catalysts provides ample reactive sites to facilitate the carbon dioxide-to-ethanol conversion. The researchers also believe that the approach could be scaled for industrial  applications, such as storing electricity generated by wind and solarpower.

The ORNL team is also planning to improve its approach to enhance the overall production rate and further study the catalyst’s properties and behaviour.

Image: ORNL’s novel process converts carbon dioxide into ethanol. Photo: courtesy of Oak Ridge National Laboratory.