Nano-spike catalysts convert carbon dioxide directly into ethanol

October 12, 2016
ORNL's Yang Song (seated), Dale Hensley (standing left) and Adam Rondinone examine a carbon nanospike sample with a scanning electron microscope. Credit: ORNL

In a new twist to waste-to-fuel technology, scientists at the Department of Energy's Oak Ridge National Laboratory 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 serendipitous.

"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 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.

"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."

ORNL researchers develop a nano-spike catalyst that converts carbon dioxide directly into ethanol. Credit: ORNL

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.

"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 researchers' initial analysis suggests that the spiky textured surface of the catalysts provides ample reactive sites to facilitate the -to-ethanol conversion.

"They are like 50-nanometer lightning rods that concentrate electrochemical reactivity at the tip of the spike," Rondinone said.

ORNL researchers developed a catalyst made of copper nanoparticles (seen as spheres) embedded in carbon nanospikes that can convert carbon dioxide into ethanol. Credit: Oak Ridge National Laboratory

Given the technique's reliance on low-cost materials and an ability to operate at room temperature in water, the researchers believe the approach could be scaled up for industrially relevant applications. For instance, the process could be used to store excess electricity generated from variable power sources such as wind and solar.

"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."

The researchers plan to refine their approach to improve the overall production rate and further study the catalyst's properties and behavior.

ORNL's Yang Song, Rui Peng, Dale Hensley, Peter Bonnesen, Liangbo Liang, Zili Wu, Harry Meyer III, Miaofang Chi, Cheng Ma, Bobby Sumpter and Adam Rondinone are coauthors on the study, which is published as "High-Selectivity Electrochemical Conversion of CO2 to Ethanol using a Copper Nanoparticle/N-Doped Graphene Electrode."

Explore further: New approach to dynamically tune how a catalyst operates

More information: Yang Song et al. High-Selectivity Electrochemical Conversion of COto Ethanol using a Copper Nanoparticle/N-Doped Graphene Electrode, ChemistrySelect (2016). DOI: 10.1002/slct.201601169

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10 comments

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rrrander
1.8 / 5 (10) Oct 13, 2016
Getting rid of horribly cost ineffective solar and wind completely would be the best option.
optical
Oct 13, 2016
This comment has been removed by a moderator.
tear88
5 / 5 (1) Oct 13, 2016
What wonderful possibilities. Convert CO2 directly to ethanol; mitigate anthropogenic climate change and get booze at the same time.

rrander: Yeah, because fossil fuels are so efficient. (/s)
optical: I have no idea how cold fusion relates to this article, and I doubt there's much connection between muons and nanoscale carbon.
Shelgeyr
not rated yet Oct 13, 2016
tear88: In terms of energy density compared to the "alternatives", rrander is basically correct in that fossil fuels are quite efficient.
RealScience
5 / 5 (4) Oct 13, 2016
@Shelgeyr: rrander was clearly referring to cost efficiency, not energy density.

The funny thing is, rrander is right, but NOT in the way he/she/it thinks - at the rate that solar costs are dropping we can now use COST-EFFECTIVE solar instead of the older cost-ineffective solar. Solar PV's problem is not cost - it has recently been the lowest price in sunny areas even without subsidies (e.g., Chile), it is storage, and this article is on how to store energy.

More relevant to energy density, although ethanol is not as energy-dense as hexane (or Diesel), it comes reasonably close and it sure beats current batteries. (And ironically the fossil fuels that you praise are really chemically-stored SOLAR energy...)
rakooi
5 / 5 (3) Oct 13, 2016
With Solar and Wind now extremely competitive with even dirty old Coal Generated Electricity, this is a wonderful new entry to fight Global Warming & its resulting climate changes.
KenC
5 / 5 (3) Oct 14, 2016
I'm looking forward to updates on this. It could be a game changer if it becomes practical and cost effective on a large scale. It's hitting on two levels, absorbing CO2 and creating ethanol. The great advantage of being able to turn Solar energy and CO2 into ethanol it that we have a ready market and distribution system for energy dense ethanol. It can be used (blended) in a modern hybrid vehicle (all gasoline vehicles actually), no issue with charging infrastructure, range anxiety, and cost of batteries.

And instead of a negative of using food crops and fossil fuels (fertilizer and tractor fuel) to grow corn for ethanol (and more energy to distill it), we get it from CO2. This is great - but can it be brought to market? Let's hope so!
gkam
1 / 5 (4) Oct 14, 2016
"Getting rid of horribly cost ineffective solar and wind completely would be the best option."
-------------------------------------------
Want to see my system? Our car and house run mostly on sunshine.

Does your car make noise and stink?
TheGhostofOtto1923
3 / 5 (2) Oct 14, 2016
Want to see my system?
Yeah. Post pics on your little website instead of sending fake ones out to select individuals.
Our car and house run mostly on sunshine
No, we know for a fact that george kamburoffs EV and PV run entirely on bullshit. He only made them up so he could pretend to be an authority, like he did his phony MS, his stolen valor medals, his fake engineer education and experience, etcetcetc.

And because that's what lying cheating psychopaths do.
rustolio
5 / 5 (1) Oct 14, 2016
I wonder how long the catalyst lasts. If production of the catalyst is cheap and it has a reasonable lifetime, this could be huge.

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