Proven one-step process to convert CO2 and water directly into liquid hydrocarbon fuel

February 22, 2016
From left: Mohammad Fakrul Islam, Frederick MacDonnell, Wilaiwan Chanmanee and Brian Dennis, all of UTA. Credit: UTA

A team of University of Texas at Arlington chemists and engineers have proven that concentrated light, heat and high pressures can drive the one-step conversion of carbon dioxide and water directly into useable liquid hydrocarbon fuels.

This simple and inexpensive new sustainable fuels technology could potentially help limit global warming by removing from the atmosphere to make fuel. The process also reverts oxygen back into the system as a byproduct of the reaction, with a clear positive environmental impact, researchers said.

"Our process also has an important advantage over battery or gaseous-hydrogen powered vehicle technologies as many of the hydrocarbon products from our reaction are exactly what we use in cars, trucks and planes, so there would be no need to change the current fuel distribution system," said Frederick MacDonnell, UTA interim chair of chemistry and biochemistry and co-principal investigator of the project.

In an article published today in the Proceedings of the National Academy of Sciences titled "Solar photothermochemical alkane reverse combustion," the researchers demonstrate that the one-step conversion of carbon dioxide and water into and oxygen can be achieved in a photothermochemical flow reactor operating at 180 to 200 C and pressures up to 6 atmospheres.

"We are the first to use both light and heat to synthesize liquid hydrocarbons in a single stage reactor from carbon dioxide and water," said Brian Dennis, UTA professor of mechanical and aerospace engineering and co-principal investigator of the project.

"Concentrated light drives the photochemical reaction, which generates high-energy intermediates and heat to drive thermochemical carbon-chain-forming reactions, thus producing hydrocarbons in a single-step process."

Duane Dimos, UTA vice president for research commended the researchers on their success.

"Discovering a one-step process to generate renewable hydrocarbon fuels from carbon dioxide and water is a huge achievement," Dimos said. "This work strengthens UTA's reputation as a leading research institution in the area of Global Environmental Impact, as laid out in our Strategic Plan 2020."

The hybrid photochemical and thermochemical catalyst used for the experiment was based on titanium dioxide, a white powder that cannot absorb the entire visible light spectrum.

"Our next step is to develop a photo-catalyst better matched to the solar spectrum," MacDonnell said. "Then we could more effectively use the entire spectrum of incident light to work towards the overall goal of a sustainable solar liquid fuel."

The authors envision using parabolic mirrors to concentrate sunlight on the catalyst bed, providing both heat and photo-excitation for the reaction. Excess heat could even be used to drive related operations for a solar fuels facility, including product separations and water purification.

The research was supported by grants from the National Science Foundation and the Robert A. Welch Foundation. Wilaiwan Chanmanee, postdoctoral research associate in mechanical and aerospace engineering, and Mohammad Fakrul Islam, graduate research assistant and Ph.D. candidate in the department of Chemistry and Biochemistry at UTA, also participated in the project.

MacDonnell and Dennis have received more than $2.6 million in grants and corporate funding for sustainable energy projects over the last four years.

MacDonnell and Dennis' investigations also are focused on converting natural gas for use as high-grade diesel and jet fuel. The researchers developed the gas-to-liquid technology in collaboration with an industrial partner in UTA's Center for Renewable Energy and Science Technology, or CREST, lab, and are now working to commercialize the process.

MacDonnell also has worked on developing new photocatalysts for hydrogen generation, with the goal of creating an artificial photosynthetic system which uses solar energy to split water molecules into hydrogen and oxygen. The hydrogen could then be used as a clean fuel.

Explore further: Researchers devise more efficient materials for solar fuel cells

More information: Solar photothermochemical alkane reverse combustion, PNAS,

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1.3 / 5 (7) Feb 22, 2016
I wonder how many decades it would take for people to start complaining about the companies stealing all the carbon dioxide out of the atmosphere to make cheap fuel based on this research. Luckily Venus has thousands of years worth that we can start tapping once we have floating factories in its atmosphere. The main problem is we don't have a skyhook that can be used to grab the fuel yet.
1.6 / 5 (7) Feb 22, 2016
Jeffhans1: I know what ecologic movements will do: Stop taking CO2 from atmosphere! Models from 2050 predict that in 2100 we'll have Ice Age/global cooling/trendier name.
5 / 5 (13) Feb 22, 2016
I wonder how many decades it would take for people to start complaining about the companies stealing all the carbon dioxide out of the atmosphere

I know what ecologic movements will do: Stop taking CO2 from atmosphere! Models from 2050 predict that in 2100 we'll have Ice Age/global cooling/trendier name.

Since the CO2 is released back into the atmosphere upon use of the fuel....
4.3 / 5 (6) Feb 23, 2016
"Since the CO2 is released back into the atmosphere upon use of the fuel...."

Exactly. What they have done is develop a nonbiological version of photosynthesis, and just like green plants, these will NOT deplete the atmosphere's CO2. In fact, unless we bury the resulting hydrocarbons, it won't reduce the CO2 level at all. If all of our fossil fuels were replaced by this, it would stop the rise in CO2 levels.
3 / 5 (2) Feb 23, 2016
sounds cool *crosses some fingers*
1 / 5 (2) Feb 23, 2016
Another technology that won't be developed for practical use until the oil and gas runs dry.

Without careful management, if the petro-chemical industry is suppressed then the entire worlds economy would collapse and civilisation, as we know it, would cease to exist.

Any new tech that can provide easily accessible low cost energy is doomed to be largely ignored ( or worse, hidden away) because Its simply too dangerous to our current civilisation.

Any introduction of substantive alternative energy sources is, a least, 50 to 100 years away.

Still, it's good to know there are viable alternatives going forward.

5 / 5 (5) Feb 23, 2016
If all of our fossil fuels were replaced by this, it would stop the rise in CO2 levels.

Of course it would stop the rise in CO2 concentration.
It would not reduce the CO2 concentration.
This may indeed not be enough.
5 / 5 (6) Feb 23, 2016
This may indeed not be enough.

I think this can be said about any one solution. But put them all together and it may be.
In any case it's smart to have a diverse set of solutions. Some will come with unintended side effects.

While having many solutions in place means that side effects are *more* likley it also means:
- side effects will be smaller, because the problematic solution will only be (a small) part of the overall system.
- it's far easier to drop that problematic solution quickly in favor of strengthening another solution that is already in place (instead of building up a new replacement solution from scratch.)
1.7 / 5 (6) Feb 23, 2016
It just keeps on getting better and better. Scientific American and other publications have already shown how we can be self-supporting with alternative energy, but these new technologies are going to make it even easier cheaper, and better for us.
3.7 / 5 (3) Feb 23, 2016
@Jeffhans1 "The main problem is we don't have a skyhook that can be used to grab the fuel yet." Just to set the record straight, there is a "skyhook" operating in a small town called Squamish in BC, Canada. this operation has huge fans that blow outside air through special collectors/scrubbers that remove the CO2 from the air passing through. I can see this new technology described in the article being a perfect fit to this facility doing the CO2 capture. The future is here and ready to go. Leave the oil in the ground!
1 / 5 (3) Feb 23, 2016
Of course it would stop the rise in CO2 concentration.

CO2 levels have been higher and lower in the past, before humans. So, have those natural processes that drove this, all stopped?
4 / 5 (4) Feb 23, 2016
@Antigoracle time to get your head out of your backside. Oil and coal are behind this CO2 mess we're in and the propaganda pushed by those corporations has too many of us brainwashed into thinking that's incorrect. That its natural. If it was "natural" the rise in CO2 would take thousands of years, not just 200. That's us doing that. If we don't get our collective heads out of our backsides we will have over 50C summertime temperatures killing us off faster than our own nonsense. Happened last summer in India and it's predicted that daytime temperatures in the middle east will average 55C every summer. Seems the addage that "what goes around, comes around" is applicable here. The bulk of the oil which put the bulk of the CO2 in the air came from the middle east, now they'll pay the price. It's going to get really ugly out there, just wait.
1 / 5 (3) Feb 23, 2016
OK. You keep your head up your backside and mumble when was the last time you consumed fuel or power generated from oil and coal?
1 / 5 (1) Feb 23, 2016
This seems almost too easy and cheap to be true...only 6 atm and 200 C .. really?
I would imagine it would work even better with black titania instead of white titanium oxide.
It could be seriously dangerous for some industry....
5 / 5 (1) Feb 23, 2016
Here is an unrealistic plan that may be effective.
To stabilise the CO2 concentration and thus the temperature rise,
the production of fossil fuels is phased out.
Fuel is produced from atmospheric CO2 or vegetal C.
We face a sea level rise of 20-30 meters over a few centuries if we stabilise.
So reduction is needed.
A CO2 reduction of 1 ppm requires the production of 1 km^3 of C per ppm CO2 reduction to be dumped in the ocean or used in a manner that does not release it as CO2.
We are lucky if this works since the reduction of the land ice may be irreversible.
3 / 5 (2) Feb 23, 2016
KelDude.......antigoracle will NEVER get his head out of his back side. It has been there far to long. Removal at this stage would expose said head to a level of fresh air that would be immediately lethal, not to mention the risk of bleeding out from the torn arteries.........
not rated yet Feb 24, 2016
Phys1: Not really unrealistic. Compress the carbon into bricks and store it in abandoned coal mines! Surface mines would be easy, just fill the hole and put the dirt/rock back on top. Underground mines would take a little more effort, but the same infrastructure and workers that took the coal out should be able to put the bricks in. It was actually suggested that West Virginia mines be used to store compressed garbage several years ago, so carbon blocks should be much less controversial.

And, if we ever need the carbon, we'll know exactly where to find it. We're just taking the carbon we dug from the ground out of the air and putting it back where it came from.
not rated yet Feb 24, 2016
Antigoracle: If he lives in the northwest US he might not be using electricity from coal or oil. Water, wind, and nuclear provide most of the Northwest's power, and they're working on closing the remaining coal burning plants.
not rated yet Feb 24, 2016
There has been a few articles on here as well where models have suggested that if you radically decrease the 'weather manipulation' then there would be a bullwhip effect of sorts that will be an order of magnitude more severe than what we experience now.
I saw most of the regular commenters comment on those articles as well so I doubt I'd have to go to more detail.
This zero sum creation is great and if implemented in stages over 100(?) or more years, could solve the 'warming' issue. Not for our generation or even the next, but given all the information, it's a marathon not a sprint and nothing will come out of rushing.
1 / 5 (4) Feb 24, 2016
Oil or coal? We do not use any of those for power in our service territory, which is 94,000 square miles.
3 / 5 (2) Feb 24, 2016
Oil or coal? We do not use any of those for power in our service territory, which is 94,000 square miles.

What vehicle was your wife spending $150 a month on gasoline?
1 / 5 (5) Feb 24, 2016
Poor goricle has now a fixation to prove I wasted gas before I bought solar PV and a electric vehicle. Finding an eco-freak like me who has actually done what he proposes throws the Deniers for a loop.

How many miles are you going to put on your stinker this year, Goricle? Is it a diesel, the worst of all? I'll bet you spread your Diesel stink everywhere you go.
1 / 5 (4) Feb 24, 2016
Is it a Diesel, Goricle??
3 / 5 (2) Feb 24, 2016
Caught in the web of their LIES, the Pathological Liar's last resort is to do what it does best; fabricate lies about others.

What vehicle was your wife spending $150 a month on gasoline?
Does she know she married a Pathological Liar?
1 / 5 (1) Feb 25, 2016
There is an inherent trade-off in the design.

From experience with a similar concept, although different reaction mechanism/ process, they capture CO2, add H20, crack and reform it via a novel photothermochemical reaction, with what I perceive to be a modified water gas shift reaction through thermal pressure phase shift of superheated/supercritical steam (wiki:destructive distillation/ steam cracking; also look into superheated water in a microwave & nucleation sites) with increased reactivity due to the catalytic nature of powdered TiO2 for both cracking/reformation processes (curious if they tried AlO2, or Al-Ti-O2 or Ni-Ti-O2).

The reformed fuel, albeit cleaner with less contaminates than traditional kitchen sink oil/coke derived fuels, the CO2 is again created/ cycled from typical combustion outputs, as mentioned above, along with our friendly Nx/NOx/COx & other cmpds, resulting from air composition.

My concern: Water, in general, is a very precious natural resource...
1 / 5 (3) Feb 28, 2016
Carbon is not pollution. The Jurassic CO2 levels where 3000ppm, plants where Jurassic!
Horticulturalists use CO2 enrichment to triple plant growth is well known.
Roses optimum CO2 level is 1200ppm
Vostok ice records clearly show carbon lags heat by 800 years, impossible for CO2 to "trap" heat if the Vostok ice records clearly shoe a CO2 lag of 800 years...
1 / 5 (4) Feb 28, 2016
Unreal, you are grasping at straws. They found how the gases diffuse upward in the snow and ice before they are set after decades. It made it look like the gases followed the temperature instead of leading it. We now know better, and can see for ourselves in the last 100 years in other examples and changes.
1 / 5 (1) Feb 28, 2016
It should be emphasised that CO2 + water is not a fuel. You still must add energy to get a fuel.
not rated yet Mar 04, 2016
The energy added is included in the system: heat and light.

Such a system would seem, er.. highly energetic. read: explosive
1 / 5 (1) Mar 31, 2016
we could easily imagine a system like....existing concentrated solar thermal plants
why explosive ? Hydrocarbon usually need O2 to combust...if you produce this hydrocarbon in water with disolved CO2 without 02... there should not be any explosion.

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