Waste to Fuel Surprise: Researchers Accidentally Convert Carbon Dioxide into Ethanol

Oak Ridge National Laboratory scientists have developed an electrochemical process that uses tiny spikes of carbon and copper to turn carbon dioxide, a greenhouse gas, into ethanol. Their finding, which involves nanofabrication and catalysis science, was unexpected. "We discovered somewhat by accident that this material worked," said ORNL's Adam Rondinone. "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." 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 the nanotechnology-based catalyst which contains multiple reaction sites, the solution of carbon dioxide dissolved in water turned into ethanol with a yield of 63 percent. Typically, this type of electrochemical reaction results in a mix of several different products in small amounts. The catalyst's novelty lies in its nanoscale structure, consisting of copper nanoparticles embedded in carbon spikes. This nano-texturing approach avoids the use of expensive or rare metals such as platinum that limit the economic viability of many catalysts.

Transcript

00:00:02 Here at the Center for Nanophase Materials Sciences we're using nanotechnology to study how we control chemical reactions on catalysts. We were actually studying how to take carbon dioxide and convert it to what we thought was going to methanol, turned out to be ethanol, which was very scientifically interesting and it was unexpected because we didn't think the

00:00:21 catalyst were working with would do the entire reaction on its own. We originally started trying to grow a type of catalyst based on the material called graphene and as it turned out with the equipment we have we couldn't make graphene, but we could make these little tiny spikes. So these little spikes are actually like tiny lightning rods and so they actually taper down to a tip this

00:00:42 just a few atoms thick and what that does is it concentrates the electric field right there at the tip and creates a very high electric field that you wouldn't get a normal flat catalyst. One of the nice things about this catalyst is actually has a yield of around 63, 65-percent. We measured as high as 70 percent depending on the sample, which means that of all the

00:01:04 carbon dioxide all the electricity is going into it, you don't waste much of it the majority of it ends up actually converted to ethanol. It matters technologically because ethanol is a fuel. You can use it in the current vehicle fleet right with no modifications. CO2 or carbon dioxide is a problem right now and if you can use it

00:01:24 then you're preventing from going the atmosphere. And because this reaction operates at room temperature it can be turned on and off very easily with no real energy penalty and so we see this is a way that you could store extra electricity from the grid. Typically the grid is destabilized by variable sources like solar and went and so there's a limit to

00:01:47 how much variable electricity or variable sourced electricity we can put into the grid. If we could have a variable load that we turn on and off it will then it gives us a wave actually sucking that electricity up and using it