by Sudeepthi Ravipati (’24) | March 29, 2021
Fossil fuels have been the source of industrial prosperity for several decades. The process of burning these fuels, however, has led to an abundance of greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Multiple countries across the globe rely on these fuels, and the United States itself obtains 81% of its total energy from a variety of fossil fuels. One source of our high carbon dioxide levels is air transportation, an important and growing sector of our economy.
For many years, scientists have attempted to mitigate the aviation industry’s sizable environmental footprint. If we recycled the carbons that airplanes and jets emit into renewable energy, greenhouse gas emissions would not increase as rapidly. However, the process of creating jet fuel is difficult because the fuel consists of lengthy carbon chains, and most hydrocarbon synthesis processes form short chains rather than the desired long chain hydrocarbons. Additionally, such efforts often require expensive catalysts and lengthy process times, with most attempts becoming even more expensive than fossil fuels.
At the University of Oxford, however, a group of researchers has been able to convert carbon dioxide into jet fuel using an iron-based catalyst. This inexpensive catalyst has immense potential for the many benefits it could induce. “The recycling of carbon dioxide as a carbon source for both fuels and high-value chemicals offers considerable potential for both the aviation and petrochemical industries,” the researchers say in their paper published in Nature Communications. The fe-mn-k catalyst that the group created consists of iron along with manganese, which fastens iron activity, and potassium, which increases carbon absorption and deposition. The researchers used the Organic Combustion Method (OCM), in which iron, manganese, potassium, and citric acid are mixed and heated at 50 degrees Celsius to create a slurry based on citric acid. The paste is then heated again at 350 degrees Celcius for four hours, resulting in an ultrafine, crystalline, and carbon-free powder. Byproducts of OCM include ethylene, propylene, and butene, materials crucial to the petroleum industry.
Researchers soon plan to scale the catalyst to promote larger test samples and applications. The hydrocarbon process is tricky, but Joshua Heyne, a mechanical and chemical engineer at the University of Dayton, tells Wired, “This does look different, and it looks like it could work. 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.” Despite the possible issues that researchers could encounter in scaling, this new catalyst is an immense advancement in biofuels and will take us one step closer to reducing the aviation industry’s carbon footprint.