Chemists accidentally turn carbon dioxide to ethanol in breakthrough study
The process uses spikes of carbon and copper to turn CO2 into the fuel
19 Oct 2016
Department of Energy's Oak Ridge National Laboratory
In a fortuitous turn of events, researchers in Tennessee have turned carbon dioxide into ethanol in what they’re calling a "new twist to waste-to-fuel technology".
Scientists at the Department of Energy’s Oak Ridge National Laboratory developed an electrochemical process that uses tiny spikes of carbon and copper to turn CO2 into the fuel.
In particular, 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 this catalyst, the solution of carbon dioxide dissolved in water and turned into ethanol. Typically, this type of electrochemical reaction results in a mix of several different products in small amounts.
The researchers developed a catalyst made of copper nanoparticles (seen as spheres) embedded in carbon nanospikes that convert carbon dioxide into ethanol
Department of Energy’s Oak Ridge National Laboratory
“We discovered somewhat by accident that this material worked,” said ORNL’s Adam Rondinone, lead author of the team’s study published in 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.”
“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 is unique and effective because of its nanoscale structure, which contains copper nanoparticles embedded on carbon spikes. This approach meant that the researchers didn’t need to use expensive or rare metals, such as platinum, which typically push costs up and make the process less economically viable.
“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 added.
The researchers’ initial analysis suggests the spiky textured surface of the catalysts provides multiple sites where the reaction can take place, and ultimately help turn carbon dioxide into ethanol.
“They are like 50-nanometre lightning rods that concentrate electrochemical reactivity at the tip of the spike,” Rondinone said.
Given the technique’s reliance on low-cost materials and the fact it can be operated at room temperature in water, the researchers believe the approach could be scaled up. For example, the process could be used to store excess electricity generated from power sources such as wind and solar. The researchers said they will refine their approach to improve production rate and further study the catalyst’s properties.
The work was supported by DOE’s Office of Science and used resources at the ORNL’s Centre for Nanophase Materials Sciences.