Between the COVID-19-related decline in air travel and increased scrutiny on airplane fuel consumption, it’s been a rough time for airlines. But in new research, scientists from the University of Oxford offer a novel way to turn waste CO2 into usable hydrocarbons—and even into jet fuel.
The secret is a complex chemical catalyst, made by blowing up elements and using materials like citric acid or even regular household flour as catalyst fuels.
Jet engines are, surprisingly, pretty robust. They can accept a wide variety of fuels, including a new partial biomass regiment just introduced by England’s Royal Air Force. The marketplace of ideas is wide open to people with new concepts for making the airplanes run, with implications for entire fields like defense and research.
That’s also because even during the worst passenger flight year on record, cargo still flies, including international mail, fresh food, and consumer goods. (Most manufactured goods and even a lot of fresh food are still shipped on, you know, ships. The cost saving to companies with well-established oversea logistics is enormous, and cargo ships are surprisingly environmentally efficient compared with other options.)
So how do you turn waste CO2 not just into usable hydrocarbons for fuel, but also part of a new and carbon-neutral supply chain because of the cyclical reuse of CO2?
This involves making a chemical catalyst using a chemical reaction called organic combustion, then using the catalyst to add hydrogen atoms, the same process that turns regular fats into shelf-stable, but trans-fat-rich hydrogenated ones.
The catalyst is iron, manganese, and potassium, chemically assembled using a relatively new process called the organic combustion method (OCM). This replaces a method with a conspicuous downside. The Oxford researchers explain:
“Iron-based catalysts are typically prepared by chemical co-precipitation routes, which unfortunately consumes significant amounts of water. Among the catalyst synthesis methods, the so-called OCM is recognized as an energy-efficient and economically viable approach for the one-pot synthesis of a variety of nanostructured solid catalysts.”
Yes, here the idea of one pot is just as appealing as it is for making family dinners, and OCM also uses less water. In this paper, the researchers experimented with OCM fuels like citric acid, where each results in a slightly more or less catalytic—meaning, literally, how effective it is as a catalyst—chemical mixture. One family of fuels stood out.
“In general, the Fe–Mn-K catalysts synthesised with carboxylic acids and polycarboxylic acids as fuels showed superior catalytic performances than those prepared using urea and sugar (glucose) and the catalyst prepared without fuel,” the scientists explain.
They even tested regular flour and sugar. By exploring a huge range of options, the scientists hope to demystify this process, where even less-efficient processes could still save a lot of carbon dioxide. Once the catalyst materials are prepared into ready-to-use powders, they’re used to turn carbon dioxide first into carbon monoxide or methanol and then into jet fuel.
“This, then, is the vision for the route to achieving net-zero carbon emissions from aviation,” the researchers conclude. “A fulcrum of a future global zero-carbon aviation sector.”