Scientists discover a novel way to make ethanol without corn or other plants

Apr 09, 2014
Stanford scientists Matthew Kanan and Christina Li have created an oxide-derived copper catalyst that converts carbon monoxide to ethanol. The catalyst consists of a continuous network of copper nanocrystals with well-defined grain boundaries. The nanocrystalline network may be critical for producing ethanol, the scientists say. Credit: Matthew Kanan, Stanford University

Stanford University scientists have found a new, highly efficient way to produce liquid ethanol from carbon monoxide gas. This promising discovery could provide an eco-friendly alternative to conventional ethanol production from corn and other crops, say the scientists. Their results are published in the April 9 advanced online edition of the journal Nature.

"We have discovered the first metal catalyst that can produce appreciable amounts of from carbon monoxide at room temperature and pressure – a notoriously difficult electrochemical reaction," said Matthew Kanan, an assistant professor of chemistry at Stanford and coauthor of the Nature study.

Most ethanol today is produced at high-temperature fermentation facilities that chemically convert corn, sugarcane and other plants into liquid fuel. But growing crops for biofuel requires thousands of acres of land and vast quantities of fertilizer and water. In some parts of the United States, it takes more than 800 gallons of water to grow a bushel of corn, which, in turn, yields about 3 gallons of ethanol.

The new technique developed by Kanan and Stanford graduate student Christina Li requires no fermentation and, if scaled up, could help address many of the land- and water-use issues surrounding ethanol production today. "Our study demonstrates the feasibility of making ethanol by electrocatalysis," Kanan said. "But we have a lot more work to do to make a device that is practical."

Novel electrodes

Two years ago, Kanan and Li created a novel electrode made of a material they called oxide-derived copper. They used the term "oxide-derived" because the metallic electrode was produced from copper oxide.

"Conventional copper electrodes consist of individual nanoparticles that just sit on top of each other," Kanan said. "Oxide-derived copper, on the other hand, is made of copper nanocrystals that are all linked together in a continuous network with well-defined grain boundaries. The process of transforming into metallic copper creates the network of nanocrystals."

For the Nature study, Kanan and Li built an electrochemical cell – a device consisting of two electrodes placed in water saturated with . When a voltage is applied across the electrodes of a conventional cell, a current flows and water is converted to oxygen gas at one electrode (the anode) and hydrogen gas at the other electrode (the cathode). The challenge was to find a cathode that would reduce carbon monoxide to ethanol instead of reducing water to hydrogen.

"Most materials are incapable of reducing carbon monoxide and exclusively react with water," Kanan said. "Copper is the only exception, but conventional copper is very inefficient."

In the Nature experiment, Kanan and Li used a cathode made of oxide-derived copper. When a small voltage was applied, the results were dramatic.

"The oxide-derived copper produced ethanol and acetate with 57 percent faradaic efficiency," Kanan said. "That means 57 percent of the electric current went into producing these two compounds from carbon monoxide. We're excited because this represents a more than 10-fold increase in efficiency over conventional copper catalysts. Our models suggest that the nanocrystalline network in the oxide-derived copper was critical for achieving these results."

Carbon neutral

The Stanford team has begun looking for ways to create other fuels and improve the overall efficiency of the process. "In this experiment, ethanol was the major product," Kanan said. "Propanol would actually be a higher energy-density fuel than ethanol, but right now there is no efficient way to produce it."

In the experiment, Kanan and Li found that a slightly altered oxide-derived copper catalyst produced propanol with 10 percent efficiency. The team is working to improve the yield for propanol by further tuning the catalyst's structure.

Ultimately, Kanan would like to see a scaled-up version of the catalytic cell powered by electricity from the sun, wind or other renewable resource.

For the process to be carbon neutral, scientists will have to find a new way to make carbon monoxide from renewable energy instead of fossil fuel, the primary source today. Kanan envisions taking carbon dioxide (CO2) from the atmosphere to produce carbon monoxide, which, in turn, would be fed to a copper catalyst to make liquid fuel. The CO2 that is released into the atmosphere during fuel combustion would be re-used to make more carbon monoxide and more fuel – a closed-loop, emissions-free process.

"Technology already exists for converting CO2 to carbon monoxide, but the missing piece was the efficient conversion of carbon monoxide to a useful fuel that's liquid, easy to store and nontoxic," Kanan said. "Prior to our study, there was a sense that no catalyst could efficiently reduce carbon monoxide to a liquid. We have a solution to this problem that's made of , which is cheap and abundant. We hope our results inspire other people to work on our system or develop a new catalyst that converts to fuel."

Explore further: Newly discovered catalyst could lead to the low-cost production of clean methanol

More information: Electroreduction of carbon monoxide to liquid fuel on oxide-derived nanocrystalline copper, Nature, dx.doi.org/10.1038/nature13249

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User comments : 26

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betterexists
3.5 / 5 (4) Apr 09, 2014
I though only Yeast was crazy; Copper seems to beat it in Craziness!
winthrom
5 / 5 (1) Apr 09, 2014
What efficiencies are needed to have a sustainable closed loop system?
CO2 ==> CO ==> H5C2O ==> CO2
I left out the equation balancing since the article did also.
Pejico
Apr 09, 2014
This comment has been removed by a moderator.
Scottingham
4.8 / 5 (5) Apr 09, 2014
but that energy could be solar, wind, nuclear
Caliban
4.8 / 5 (4) Apr 09, 2014
Pejico say:

You cannot create a fuel from carbon dioxide without adding of another fuel. This oxide is already a product of burning of fuel and no matter, how efficient the catalyst may be, you'll need another energy to convert it into usable fuel.


Scottingham say:

but that energy could be solar, wind, nuclear


Yes, yes!

Article say:

"Ultimately, Kanan would like to see[...]the catalytic cell powered by electricity from the sun, wind or other renewable resource.

For the process to be carbon neutral, scientists will have to [...]make carbon monoxide from renewable energy instead of fossil fuel[...]. Kanan envisions taking carbon dioxide (CO2) from the atmosphere to produce carbon monoxide, which, in turn, would be fed to a copper catalyst to make liquid fuel. The CO2 that is released into the atmosphere during fuel combustion would be re-used to make more carbon monoxide and more fuel – a closed-loop, emissions-free process"
NoTennisNow
1.5 / 5 (2) Apr 09, 2014
Fundamental chemistry (and chemical engineering as well since I am a chemical engineer that has consulted in the energy sector regarding fossil fuel combustion, but I digress...) is great, but no how way anytime can you can base any product on mining CO2 from air. Assuming that you have a feed stock of air, extracting all of the CO2 from air with 200 ppm CO2 would yield about 0.52 lb-moles CO2 which equates to 23 pounds of CO2. But in order to do this first step you would need an extraction process that will consume a large amount of energy to perform the extraction which in turn would require a large capital expenditure and ongoing expenditures to service the project.

Put this another way, before looking at a project, all factors must be considered. Put another way, focus on something practical.

One could always use a more concentrated CO2 stream to feed the CO2 needed for the reaction, but gas cleanup, operating costs and so forth wood need to be considered.

hangman04
4.5 / 5 (2) Apr 10, 2014
there are a lot of industries that use fossil end that exhaust CO2. Since there is also some expensive designs to capture it and store it, and considering the scalability of this new alternative wouldn't make sense to equip all these facilities with future ethanol / propanol stations that would either be financially self sufficient if not profitable, or at least they will substantially decrease the cost of CO2 capture (similar to the new concept of self sufficient waste water cleaning facilities that can benefit the grid).
antialias_physorg
3.5 / 5 (4) Apr 10, 2014
Using this in exhausts of CO2 burning industries isn't sensible. The method uses more energy than you get back burning the ethanol. (Additionally you wouldn't be sequestering the CO2, you'd just be releasing it a short time later).

This only makes sense as a storage medium if it's somewhat efficient (low losses between creation and usage of the ethanol) to buffer intermittent energy sources.
betterexists
1.8 / 5 (5) Apr 10, 2014
So much Energy is waiting for us to grab in the form of Vocanoes;
WE ARE IGNORING IT.
Zillions of Heat Energy capturing devices should be rolled around continuously above the surface of Volcanoes.
Rolling belt conveyors come to mind. Robots can be used in a myriad ways at those dangerous places.
Drones/unmanned giant airplanes can carry those devices back & forth from safe areas to the areas of active volcanoes.
Tiny Termites & Ants at ant hills come to mind too; Robots should be able to emulate them. They are after all servants of humans!
betterexists
1 / 5 (4) Apr 10, 2014
Chinese built a multi-storied hotel in 11 days;
With proper plans & appropriate funding, they should be able to set up above mentioned rolling belt conveyors at all active volcanoes on this planet.
Watch that Videoclip on youtube. Amazing.
betterexists
1 / 5 (2) Apr 10, 2014
usgsdotgov Website says that there are 1500 potentially active volcanoes worldwide, aside from the continuous belt of volcanoes on the ocean floor. About 500 of these have erupted in historical time. Many of these are located along the Pacific Rim in what is known as the "Ring of Fire."
Chinese built a multi-storied hotel in 11 days;
With proper plans & appropriate funding, they should be able to set up above mentioned rolling belt conveyors at all active volcanoes on this planet.
Watch that Videoclip on youtube. Amazing.
betterexists
1 / 5 (2) Apr 10, 2014
Read on qzdotcom website: Why volcanoes are the energy source of the future
So much Energy is waiting for us to grab in the form of Vocanoes;
WE ARE IGNORING IT.
Zillions of Heat Energy capturing devices should be rolled around continuously above the surface of Volcanoes.
Rolling belt conveyors come to mind. Robots can be used in a myriad ways at those dangerous places.
Drones/unmanned giant airplanes can carry those devices back & forth from safe areas to the areas of active volcanoes.
Tiny Termites & Ants at ant hills come to mind too; Robots should be able to emulate them. They are after all servants of humans!
betterexists
3 / 5 (2) Apr 10, 2014
Read on qzdotcom website: Unlike wind and solar, geothermal power never switches off. ("Why volcanoes are the energy source of the future")
antialias_physorg
5 / 5 (2) Apr 10, 2014
Unlike wind and solar, geothermal power never switches off

Geothermal is enticing. Unfortunately most places that it's been tried have experienced earthquakes as a result. So it's not without its drawbacks (i.e. several pilot powerplants have had to shut down because neighboring communities have had massive damage to buildings as a result).
betterexists
3 / 5 (2) Apr 10, 2014
I thought only Yeast was crazy; Copper seems to beat it in Craziness!

Yeast is a living being; It makes sense that the lucky yeast wants to stay drunk all the time. It beats me what good does lifeless Copper derive by playing with the dirty CO2 gas to get drunk too!
antialias_physorg
5 / 5 (3) Apr 10, 2014
Well, yeast is getting the opposite of drunk (or as Pratchett calls it: 'knurd'). Ethanol is something yeast tries very hard to keep OUT of its body (it's a waste product and would be toxic to it if it built up in the cell body).
betterexists
3 / 5 (2) Apr 10, 2014
Elaborate the same science to Copper Too
Well, yeast is getting the opposite of drunk (or as Pratchett calls it: 'knurd'). Ethanol is something yeast tries very hard to keep OUT of its body (it's a waste product and would be toxic to it if it built up in the cell body).

antialias_physorg
5 / 5 (2) Apr 10, 2014
Since copper is just a catalyst it doesn't really do anything together with the educts or the products. It just facilitates passage from one to the other. It's your friendly (read: low-cost) neighborhood liquor store.
NoTennisNow
1 / 5 (2) Apr 10, 2014
Geothermal might be the way to go for some regions. There is still the transmission question, as well. From a 2008 Pacific Gas and Electric announcement 2008 :The Geysers Geothermal Field, located 75 miles north of San Francisco, California, is the largest producer of geothermal electricity in the world. Commercial geothermal power has been generated continuously at The Geysers Field since 1960. Geothermal energy accounts for three percent of PG&E's current overall energy mix."

Iceland uses geothermal energy as well, and they have recently drilled down to a magma layer (3,000 feet I recall, but could be off). Of course Iceland is unique from a geological point of view, but still good for R&D.
plaasjaapie
3 / 5 (2) Apr 10, 2014
Oh good. We're going to make ethanol with carbon monoxide {from where, coal?} and electricity {generated how, exactly?}. Pardon me for being underwhelmed. :-p
TheGhostofOtto1923
3 / 5 (2) Apr 10, 2014
I was going to make a joke about discovering how to make ethanol from petroleum but then I see they already do this.

"Much of the ethanol produced in the world is actually a petroleum product. It is easily made by the hydrolysis of ethylene, a major petrochemical. Two million tons of petroleum-derived ethanol is produced annually. The principal suppliers are from South Africa and Saudi Arabia, but there are also large plants in the United States, Europe and Japan. Petroleum-derived ethanol (synthetic ethanol) is a widely used industrial solvent and has a considerable variety of other applications."

-2M tons. Must be cheaper than making it from corn but it still seems silly to me. Why not burn this in cars? Something don't figure-
plaasjaapie
2.3 / 5 (3) Apr 10, 2014
If South Africa is exporting ethanol, I suspect that Sasol is making it and that means they are making it from coal. I remember when I lived there in the 1980s, they discovered that you could run diesel engines on locomotives on isoproply alcohol {rubbing alcohol}. The locomotives worked fine except that when you were anywhere near them it was like you'd found yourself in the biggest massage room of a gym on the planet. :-P

The energy density of ethanol, iirc, is considerably lower than that of gasoline. That would suggest that the ethanol additive mandate that Congress instituted a few years ago has actually lowered gas mileage for our automotive fleet. You never hear anybody talk about that, though.
IamVal
3.7 / 5 (3) Apr 13, 2014
it's been a big question in recent years on how we'd store excess grid energy (read: intermittent power sources).

it's about more than energy density.. It's about practical and efficient use of the product produced. when you consider the lengths we've had to go recently to expand 'smart grid's to handle the excess engergy coming from solar (farms and individual homes) and wind in a practical way.
as far as a way to remove co2 from the atmosphere.. a pipe dream to say the least.
a valid energy pathway to consider after the oil dries up. Most certainly.
nswanberg
3 / 5 (2) Apr 14, 2014
"The challenge was to find a cathode that would reduce carbon monoxide to ethanol instead of reducing water to hydrogen." Let me get this straight, releasing hydrogen from water is a problem?? Wouldn't that sort of be the Holy Grail of energy production?
IamVal
2.3 / 5 (3) Apr 15, 2014
while hydrogen is a great rocket fuel and certainly has the energy density, it's also never a liquid and it's very volatile, not nearly the safety profile of ethanol or petrol or coal (of which most of our infrastructure is invested already). in other words its simply more practical to produce a liquid fuel in the internal-combustion-engine energy area
the headline seems to be in that it can turn a current hazzardous waste into a fuel in a closed loop combined. Both feats have been well established practice for decades separately.
antialias_physorg
3 / 5 (2) Apr 15, 2014
not nearly the safety profile of ethanol or petrol or coal


I dunno. I think the damage from a leaky hydrogen pipe would be much less than from a leaky oil pipe. Certainly you don't get the problems of having entire areas without drinking water like recently in China (or entire beaches without...beaches as in the case of any number of oil tanker/drill platform accidents)
solanum
3 / 5 (2) Apr 15, 2014
Isn't this the same things as:
http://www.archiv...aces.pdf
Except the work was completed in 2011?

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