Energy

Liquid hydrocarbon fuel created from CO2 and water in breakthrough one-step process

UTA researchers (L to R), Mohammad Fakrul Islam, Frederick MacDonnell, Wilaiwan Chanmanee and Brian Dennis, whose research is a first in producing usable liquid hydrocarbon fuel from sunlight, water and CO2
UTA researchers (L to R), Mohammad Fakrul Islam, Frederick MacDonnell, Wilaiwan Chanmanee and Brian Dennis, whose research is a first in producing usable liquid hydrocarbon fuel from sunlight, water and CO2
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UTA researchers (L to R), Mohammad Fakrul Islam, Frederick MacDonnell, Wilaiwan Chanmanee and Brian Dennis, whose research is a first in producing usable liquid hydrocarbon fuel from sunlight, water and CO2
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UTA researchers (L to R), Mohammad Fakrul Islam, Frederick MacDonnell, Wilaiwan Chanmanee and Brian Dennis, whose research is a first in producing usable liquid hydrocarbon fuel from sunlight, water and CO2

As scientists look for ways to help remove excess carbon dioxide from the atmosphere, a number of experiments have focused on employing this gas to create usable fuels. Both hydrogen and methanol have resulted from such experiments, but the processes often involve a range of intricate steps and a variety of methods. Now researchers have demonstrated a one-step conversion of carbon dioxide and water directly into a simple and inexpensive liquid hydrocarbon fuel using a combination of high-intensity light, concentrated heat, and high pressure.

According to the researchers from the University of Texas at Arlington (UTA), this breakthrough sustainable fuels technology uses carbon dioxide from the atmosphere, with the added benefit of also producing oxygen as a byproduct, which should create a clear positive environmental impact.

"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."

Known as solar photothermochemical alkane reverse combustion, the one-step conversion process turns carbon dioxide and water into oxygen and liquid hydrocarbons using a photothermochemical flow reactor operating at around 180° C to 200° C (356 to 392° F) and at pressures up to six atmospheres.

"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.

To initiate the hybrid photochemical and thermochemical reaction, a titanium dioxide (TiO2) photocatalyst was used. Titanium dioxide is very effective in the realm of hydrolysis – the breaking down of water into hydrogen and oxygen – and is a very effective catalyst under UV light, but it is not so efficient in ordinary visible light.

"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."

According to the research, the team suggests that cobalt, ruthenium, or even iron may be considered as good candidates for a new catalyst, particularly as the TiO2 in the experiment was observed to drop in photoluminescent intensity at higher pressures.

In the future, the researchers imagine parabolic mirrors could also be used to concentrate sunlight onto the catalyst in the reactor, thereby providing both the required heating and photo-excitation for the reaction to occur without the need for other external power sources. The team also believes that any excess heat created in this way may be used to help power other aspects of a solar fuels facility, such as material separation and the purification of water.

The results of this research were published in the Proceedings of the National Academy of Sciences (PDF).

Source: University of Texas at Arlington

40 comments
Racqia Dvorak
Recently the Navy announced it had found a way to do something similar with seawater, which could potentially allow for greater autonomy from ports and tanker groups. Wonder if it was the same approach.
Techjunkie88
Promising report indeed. But what does the author mean by 'inexpensive' ? Do the researchers have any idea at all about how realistic this is as a commercial solution?
notarichman
it sounds to me that it takes more energy for the conversion process than commercially viable.
NateD.Rector
Audii did this in May 2015,they were making 65 gals. of diesel a day.
BobMonteleone
Typical of such articles, there is NOT one word of the efficiency or the amount on energy input that is required to make the same unit of energy output in the synthesized hydrocarbon. How much light, pressure and temperature is required to make one gallon of syn fuel? Without those numbers and some projection for the costs involved the process is meaningless. There is little point in making a gallon of fuel if it takes a couple of hundred kilowatt hours of energy to do it. And that relation is simply not mentioned but is absolutely critical. The fact that it is not mentioned is cautionary tell that there is likely not much here. I realize that this is research at this point but someone needs to know if this avenue even shows promise and that, unfortunately, is missing.
esar
This is probably not commercially viable to make it in terms of energy in etc, but what about when the oil actually runs out! Hopefully they will have cracked fusion by then.(holds breath for very long time)
AbelGarcia
Water is most likely the record holder of adsorbing heat and having its molecular structure remaining intact. So it baffles me having CO2 dissolved in water and making a fuel in a heat engine.
PavleI.Premovic
After burning this liquid hydrocarbons you get again CO2.
erock5000
Brilliant! I've always felt that we needed a liquid fuel that uses our current distribution infrastructure and can be used in current gas- and diesel-powered vehicles with only minor modifications for alternative fuel to have the potential for widespread usage. But, I'm not a chemist for an engineer, so it's left to up to scientists like this group to make it happen. Bravo! I wish you the best!
glorybe2
I am leery of this idea. The burning of hydrocarbon fuels is a huge problem. Apparently this product is a direct replacement for gasoline and that may carry the same negative aspects of gasoline and diesel burning. As far as ships go, large ships are ultra violent producers of pollution already. At this time, seven large ships produce more pollution than the entire automotive pollution of the US every year. Concentrating on building homes, industries and cars and ships that all use less energy is much more important than making liquid fuels easier to come by.