Researchers find a surprise just beneath the surface in carbon dioxide experiment
Caltech, Berkeley Lab teams combines theory, X-ray experiments to explain what’s at work in copper catalyst
In a classic tale of science taking twists and turns before coming to a conclusion, two teams of researchers–one a group of theorists and the other, experimentalists–have worked together to solve a chemical puzzle that may one day lead to cleaner air and renewable fuel. The scientists’ ultimate goal is to convert harmful carbon dioxide (CO2) in the atmosphere into beneficial liquid fuel. Currently, it is possible to make fuels out of CO2–plants do it all the time–but researchers are still trying to crack the problem of artificially producing the fuels at large enough scales to be useful.
In a new study published the week of June 12 in the journal Proceedings of the National Academy of Sciences (PNAS), researchers report the mechanics behind an early key step in artificially activating CO2 so that it can rearrange itself to become the liquid fuel ethanol. Theorists at Caltech used quantum mechanics to predict what was happening at atomic scales, while experimentalists at the Department of Energy’s (DOE’s) Lawrence Berkeley National Lab (Berkeley Lab) used X-ray studies to analyze the steps of the chemical reaction.
The scientists are part of the Joint Center for Artificial Photosynthesis (JCAP), a DOE Energy Innovation Hub, whose goal is to convert CO2 into high-value chemical products like liquid fuels. JCAP is led by Caltech in partnership with Berkeley Lab, the Stanford Linear Accelerator Center (SLAC), and UC campuses at San Diego and Irvine.
“One of our tasks is to determine the exact sequence of steps for breaking apart water and CO2 into atoms and piecing them back together to form ethanol and oxygen,” says William Goddard (PhD ’65), the Charles and Mary Ferkel Professor of Chemistry, Materials Science, and Applied Physics, who led the Caltech team. “With these new studies, we have better ideas about how to do that.”
The metal copper is at the heart of the reaction for converting CO2 to fuel. Copper is a catalyst–a material used to activate and speed up chemical reactions–and, while it aids in the production of ethanol when exposed to CO2 and water, it is not efficient enough to make large quantities of ethanol. At Berkeley Lab, researchers exposed a thin foil sheet of copper to CO2 gas and water at room temperature. They found that the copper bound CO2 weakly and that adding water activated the CO2 by bending it into the shape needed to ultimately form the ethanol. However, when the theorists at Caltech used quantum mechanics and computer models to predict the atomic-level details of this reaction, they found that pure copper would not bind the CO2 and that water would not activate it.
CREDIT Berkeley Lab
This left both teams scratching their heads until they noticed that the copper in the experiments contained tiny amounts of oxygen beneath its surface. The theorists went back to their quantum mechanics equations, adding in a tiny amount of sub-surface oxygen, and were happy to find their calculations all agreed with the experiments.
“We do our experiments virtually in computers,” says JCAP research scientist Hai Xiao (PhD ’15). “And this allows us to trace how the electrons and atoms rearrange themselves in the reaction, and thus unravel the correlation between the fundamental structure and the activity.”
The theorists also predicted that when too much oxygen was present, the CO2 would not be activated. Indeed, when the experimentalists deliberately added extra oxygen into the mix, this prediction was confirmed.
“This back and forth between theory and experiment is an exciting aspect of modern research and an important part of the JCAP strategy for making fuels from CO2,” says Goddard.
Subsequent X-ray studies helped further narrow down the role of the oxygen in the reaction. “Having oxygen atoms just beneath the surface–a suboxide layer–is a critical aspect to this,” says Ethan Crumlin, a scientist at Berkeley Lab. “The X-ray work brought new clarity to determining the right amount of this subsurface oxygen–and its role in interactions with CO2 gas and water–to improve the reaction.”
The scientists say that the presence of the oxygen in the copper causes some of the copper to become positively charged and this, in turn, stabilizes the CO2 so that it can bind to water and take on the bent configuration essential to eventually making ethanol.
Based on the new findings, the Caltech researchers then used quantum mechanics to predict ways to make the reaction even more efficient. In a second paper published this week in PNAS, they report that a copper surface that is striped with both neutral and positively charged copper will better speed the reaction along. The team is now using this strategy, called a Metal-Embedded-in-Oxygen-Matrix (MEOM), to predict the best oxide material–either copper or something new–to place next to the neutral copper strips to achieve the fastest reaction.
“Quantum mechanics lets us find the best ways to arrange the atoms and takes us closer to the goal of converting carbon dioxide to fuels and other useful materials,” says Goddard.
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The first PNAS paper, titled “Subsurface oxide plays a critical role in CO2 activation by Cu(111) surfaces to form chemisorbed CO2, the first step in reduction of CO2,” is authored by Crumlin, Marco Favaro, and Junko Yano of Berkeley Lab; and Xiao, Goddard, and Tao Cheng of Caltech.
The second PNAS paper, titled “The Cu Metal Embedded in Oxidized Matrix Catalyst to Promote CO2 Activation and CO Dimerization for Efficient and Selective Electrochemical Reduction of CO2,” was authored by Xiao, Goddard, Cheng, and Yuanyue Liu, a Resnick Sustainability Institute Postdoctoral Scholar at Caltech.
This research was supported by the DOE Office of Basic Energy Science and by JCAP.
Why ‘fuel’? We’re talking here about a (very inefficient) way to make pure vodka from CO2 and water, with Oxygen as a by-product.
Further, as a source of vodka, this process might actually have some commercial application.
“We do our experiments virtually in computers,”. Huh?? Did I miss something in my management degree with admittedly deficient science curriculum? Did they then actually have a piece of copper, “Goldilocks” levels of oxygen, etc etc etc? One of the best courses I had was called “The Science of Science” with a concentration on history, method, and process with a good sprinkling of Richard Feynman. There was also a heavy discussion of fraud, other scientific misconduct and “follow the money” skeptical inquiry. The course turned me into a skeptic, if not cynic, on all new scientific discovery….kept watching the Feynman videos to remind me.
Science by Press Release tends to be pretty lame. That said…….
Hot copper is a strong and effective reducing agent in Organic Chemistry. This has been known since forever.
The ultimate carbon reduction is from CO2 back into some form of hydrocarbon compound. There is nothing wrong with with doing work to understand the exact nature of the processes involved at the molecular, atomic, and even sub-atomic level.
As we all know, nano-scale reactions and materials are big field, and getting bigger, there is nothing wrong with doing research in the field.
There is nothing wrong with the science, just the press release.
Remember the press release was likely written by a journalism major who wanted to make the story “relevant”, and “interesting”, so naturally “Saving The World” might come into it.
You beat me to it and you did it better than I would have done. That said, there’s a special place in hell for PR flacks. There should be a rule that the scientists involved have to be involved in the editing process.
Hey, all you scientists out there, these press release writers are making you look real stupid!
x1000. 😉
Harmful CO2? HAHAHAHA!
Nature has already done it. The grape vine takes that nasty co2 and runs it into wine and brandy that is all the liquid fuel I need.Please send my research grant for me to make more observations.
The cheque is in the mail – trust me.
How much did this “breakthrough” cost the taxpayer?
Oh dear, oh dear. Seems someone at Caltech needs to take a little more water with their breakfast ethanol.
Where to get the energy? Down at those hydrothermal vents there are massive pressures and huge energy fluxes. And all that dissolved naughty CO2 hiding down there.
“… rearrange itself to become the liquid fuel ethanol.”
I see a bunch of corporate farmers about to be apoplectic.
If I assume for a moment that there is plenty of other energy to fuel this process (i.e. nuclear), this could be a replacement for turning farm land from fuel production to food. The process itself “solves” the problem of portable renewable energy ‘media’.
The fear of “peak oil” is over.
People are being overly negative about this. It is pretty obvious that you can investigate artificial photosynthesis as it is likely to be way more efficient than the natural one when fully understood. You then have a useful tool to remove CO2, if you want to do so, from the atmosphere. They talk just about the process, which is potentially useful, not about implementation.
I think it is fine to be highly critical of work that is politicizing poor science on global warming, but a bit low to tar with the same brush a valid study that does not pretend to be anything other than what it is.
Thanks for posting the article, made for interesting reading.
Industry is running out of cheap and easy copper now. Ever been to a copper mine? Seen the mess and equipment? and the energy needed? O&G is clean & easy peasy compared to copper.
I’m hanging onto my hoarded pennies, just in case.
(Yes, copper mines are messy and nasty, but not anymore. Copper is essential to wind turbines and they are 100% CLEAN. So, copper magically has become clean courtesy of wind turbines.)
Metals market specialists are predicting copper prices will double by 2030 due to electric car production increases. That doesn’t even allow for much sales increase. Keep those pennies! Going to be like silver coins were in the early 80’s.
That’ll be good for the economy of Chile. Not sure about the lithium market, however, as new battery technology develops.
The Carnot Cycle is alive and well last time I noticed. By the time you use 25% or so efficient solar panels to produce electricity and then use a process with loss to convert it into c2h4oh and then use heat engines to turn the c2h4oh into electricity again, your total system efficiency is pretty darn low. You might as well “go Drax” by the time all is said and done and let plants produce the biomass and then burn it. Still, an chemically interesting finding, but not a panacea for anything.
That’s what they said about electricity when it was discovered…what possible use could it have? A curious oddity they said. Or nothing would ever come of the Wright brothers fancy flying machine for the first 5 years. Even the US Navy declined much involvement with the aeroplane until about 1910. And a million other examples exist about other such discoveries and inventions. I believe this ability to convert any type of surplus energy and converting carbon dioxide efficiently into a highly efficient high density liquid fuel ensures we will stay in a future ‘carbon’ economy for the long term future. It will be a renewable ‘carbon’ future, but will ensure we transition out of fossil fuels when their price point makes them not feasible. Plus, by the time this technology is honed and polished within maybe 15-20 years, we will stabilize CO2 levels in the atmosphere at around 560-600 ppmv, a doubling from preindustrial times. Which gives us hopefully that 1.2 C temp theoretical increase and hopefully some positive feedback warmth from increased water vapour. This should keep everybody happy that all will be well for the long term future.
Their goal is apparently to remove all that harmful CO2 so that the Earth can return to its pristine, lifeless state. Of rocks and minerals. Strange goal, one would think.
Notice that there is no claim made that any of this will lead anywhere. At best, it may become practical after electric cars have replaced all ICE vehicles. I don’t believe you can power a jet engine using ethanol. Solution? Propellers and 15 hour coast to coast flights make a return.
I’ll start buying propeller manufacturer stocks.
arthur4563 June 13, 2017 at 6:56 am
I don’t believe you can power a jet engine using ethanol.
Certainly can power jet engines with ethanol, ethanol from sugar cane has been used for power generation in Brazil with gas turbines. Gas turbines have very good multi-fuel capability, that’s one reason for using them in the M1 Abrams tank (a project I worked on many years ago).
http://www.power-eng.com/articles/print/volume-117/issue-9/features/aeroderivative-gas-turbine-fuel-flexibility.html
‘… harmful carbon dioxide …’
What is the other sort like?
Fossil fuel CO2 is bad, all other is good.
Ignoring my wariness of anything published in PNAS, and not being immediately put off by the words “…maybe one day…”, I read the whole press release to the end.
I saw no hint the researchers expect the complete eventual process to be spontaneous and not require energy inputs.
An Input would be acceptable as long as the net input is negative. The more negative the better.
As for tax-payer funding, this seems a relatively low-cost investigation of some fundamental science. It is the sort of work that should be first in line when the government hands out research money.
Sure, the featured press release is just a superior bit of click-bait, but most of the reaction I see here is just cynical. Reading the comments on this thread I think the alarmists can be forgiven their sense that we’re a bunch of anti-science “deniers”.
If I remember thermodynamics correctly (a big IF), there is a balance between CO2 and C2H5OH (ethanol) in a water solution at any time (why ethanol and not a simpler methanol? Dunno, but ethanol is more pleasant). They were able to show that in the presence of copper (with a little oxygen, shown to be essential) the ethanol could be produced at all. How much of it, and how expensively, was not investigated.
I can already exchange copper for ethanol at the liquor store at a much lower price!
“The scientists’ ultimate goal is to convert harmful carbon dioxide (CO2) in the atmosphere into beneficial liquid fuel.”
Here lies Science
Antiquity-Age of Gore
R.I.P.
As a layman I look at this and think: Well, we have $6 a gallon ethanol with included taxpayers’ supplements and now they have come up, possibly, with a process to produce it at $10 a gallon ethanol while starving all plant life on the planet. The absurdity just continues to grow.
Before retirement, I had a job that depended on a model simulation which grew in sophistication over the years. Even as I retired, this simulation required constant real-world input in order to maintain accuracy. As a result I am skeptical anytime I hear that word. Sensitivity to initial conditions will get you every time.
Given an nearly infinite source of energy to run this thing, it could have merit producing biochar or possibly cellulose substitute for revitalising tired/weathered/eroded soils – such as in Chad for example.
The bio-sphere needs/uses a lot of organic carbon and current farming practices are, to put it bluntly, are strip mining it from the world’s best soils. Its is being turned into CO2, dissolving into rain and thence disappearing into the briny deep as carbonate rock. No matter how many times you recite ‘Henry’s Law, Henry’s Law or even, Henry’s Law.
A basic grasp of Entropy tells you all you need to know.
The reduced organic fraction within the soil reduces fertility, allows actual erosion (mudslides etc) and the soils retain less moisture/water. Oh no, does this mean more flooding? Like Flash Flooding. Like they get in Chad?
Water, having very high latent and specific heat contents, moderates the temperature of the soil, dirt, farmland (and hence atmosphere)= 10% of the entire surface area of this planet
So you get the double whammy. CO2 levels go up and so do average temperatures.
Wonder what causes what? Its not like soil bacteria produce CO2 or are in any way sensitive to temperature.
And then, people (even scientists, honest ones at least) put thermometers where other folks may be interested in knowing the temperature – namely where they live and where they grow food.
Same places really.
I think we all know ‘scientists’ just make up the temperature in places where they don’t have thermometers.
Me & you would do just the same- make an educated guess and you don’t get more educated than A Scientist. They are all *so* incredibly clever. Its nothing at all to do with how big their paychecks or willies are.
Mmmmm. That temp vs CO2 thing sounds familiar from somewhere……..
Well. Computer synthesized reactions. Has this been done in actuality?
I am surprised how complex systems we can model today. A crystallic structure of copper, with some oxygen in irregular positions, plus liquid water with carbon dioxide in irregular positions – amazing!
More amazing is the idea that the computer can model a here-to-unknown outcome based on possibly known inputs. That’s very close to AI. How does the computer model the unknown?
You can model how fast a rock would fall when dropped. It is a here-to-unknown outcome, based on known inputs. It is called science, not AI.
Odd that they don’t mention the energy input required to convert CO2 to ethanol. When ethanol is burned it releases CO2, water, and energy, so any catalyzed reaction that converts CO2 to ethanol must involve energy input at least a little larger than what is released by burning (since 100% efficiency is thermodynamically impossible). Are they talking about a more efficient solar energy collector?
The 64,000 dollar question is……it the ethanol produced drinkable?
You can bet if it is, it will be denatured before it ever leaves the lab.
This is a very good example on how relying on computer programs can be dangerous to the outcome. This is what happens to the Scientists associated with Climate Alarmists. There’s no way they have ALL the pertenate info to program properly…
This raises the question: if an otherwise benign process to remove all CO2 that fossil field burning adds to the atmosphere was invented, would the eco-chondriacs still remain opposed to its use?
Setting the ‘harmful CO2’ genuflect aside, this appears to be a fair bit of computational materials science combined with metallurgy, physical chemistry, organic chemistry, and iterative ‘wet’ lab testing of hypothesis. Cross sectional evaluations of near surface oxygen concentrations in the copper substrates may have been achieved by Focused Ion Beam Scanning Electron Microscopy (FIB/SEM) .
That’s the ‘real’ scientific method in action!
It also appeals to my metallurgical engineers soul that Bronze age copper substrates are the core of their catalysis experiments.