Scientists Use Iron to Turn Carbon Dioxide Into Jet Fuel

If the chemical reaction at the heart of the process can be scaled up, it could help reduce the carbon footprint of air travel

Airplane
A new chemical process uses an iron-based catalyst to turn carbon dioxide into jet fuel. So far the process has only been proven effective in lab settings, but if researchers can scale it up it could lessen the climate impact of air travel. Wolf Craft via Me Pixels under CC0

A newly developed chemical process could convert carbon dioxide into jet fuel, reports Maria Temming for Science News.

Carbon dioxide (CO2) is of course the same greenhouse gas flooding Earth’s atmosphere via the exhaust of jet engines and nearly anything else that burns fossil fuels. So, if this new chemical reaction can successfully turn CO2 into fuel for airplanes it could help reduce the carbon footprint of the aviation industry, which currently accounts for 12 percent of all global transportation carbon emissions.

The experimental process appeared in a new paper published last week in the journal Nature Communications. The researchers are hopeful that the process can be replicated at larger scales, but thus far it has only been proven in the lab, reports Eric Niiler for Wired.

“Climate change is accelerating, and we have huge carbon dioxide emissions,” Tiancun Xiao, a chemist at Oxford University and co-author of the paper, tells Wired. “The infrastructure of hydrocarbon fuels is already there. This process could help relieve climate change and use the current carbon infrastructure for sustainable development.”

Science News notes that researchers have tried to turn CO2 into fuel in the past but that the chemical reactions that emerged from these efforts required rare and expensive catalysts such as cobalt. By contrast, the strength of this new technique is in large part due to its use of a relatively inexpensive and easy to obtain iron-based powder.

In the lab, the researchers combined carbon dioxide with 662-degree heat, hydrogen, citric acid, manganese, potassium and the iron catalyst inside a pressurized stainless-steel reactor to produce a few grams of jet fuel, according to Wired.

The iron catalyst allows the carbon atoms in the CO2 molecules to detach from oxygen and form bonds with the hydrogen atoms inside the reactor. These new hydrogen-carbon molecules, called hydrocarbons, are the same molecules that make up jet fuel. Meanwhile, most of the remaining oxygen atoms also hitch themselves to hydrogen atoms to become water.

In tests lasting 20 hours, the process converted 38 percent of carbon dioxide inside the reactor into jet fuel and other substances including water, propylene and ethylene, reports Bob Yirka for Phys.org. Jet fuel made up nearly half of the various byproducts from the chemical reactions. Moreover, some of these byproducts, such as ethylene and propylene, can be used to make plastics, per Science News.

“This does look different, and it looks like it could work,” Joshua Heyne, a mechanical and chemical engineer at the University of Dayton, tells Wired. “Scale-up is always an issue, and there are new surprises when you go to larger scales. But in terms of a longer-term solution, the idea of a circular carbon economy is definitely something that could be the future.”

According to the researchers, their process could open the door to carbon-neutral air travel, because burning jet fuel made in this way would release the same amount of carbon dioxide used to manufacture the fuel.

It's still unclear whether this new process could power the jet liners of tomorrow, but Xiao tells Wired he sees "no big challenges" to scaling up, only a "need to optimize the process and make it more efficient."