Dioxycle makes ethylene from carbon emissions

Much of the plastic found in garbage bags, milk containers, and wiring insulation, among many other products, comes from ethylene, a small molecule with an enormous carbon footprint.

Steam crackers currently churn out more than 225 million metric tons (t) of ethylene annually in a carbon-intensive process that requires temperatures in excess of 750 °C and the feedstocks ethane or naphtha.

The Paris-based start-up Dioxycle wants to slash the amount of fossil fuels needed to make ethylene by using waste carbon emissions as its feedstock in a process powered by renewable electricity. The company has designed an electrolyzer that converts carbon monoxide and water into ethylene and oxygen. The device can be coupled with other technology that converts carbon dioxide into CO.

“The idea is simple,” Dioxycle cofounder and CEO Sarah Lamaison says. “We take carbon that we can recycle and turn that into ethylene.”

Displacing the steam cracker and recycling industrial emissions to make ethylene could eliminate roughly 800 million t of CO₂ equivalents each year, Lamaison says. That’s about 1–2% of the world’s carbon emissions and similar to the amount the shipping industry generates.

For now, Dioxycle plans to source carbon from the emissions of steel plants and chemical manufacturers. But the company might be able to get it from biogenic processes or direct air capture in the future.

The technology has the potential to overhaul how ethylene is made. For one thing, the industry wouldn’t be dominated by just a few companies with steam crackers, Dioxycle cofounder and chief technology officer David Wakerley says. “You would be able to make ethylene wherever you can source carbon monoxide.”

Lamaison and Wakerley had an inkling they’d work well together as company founders when they met as graduate students at the University of Cambridge in 2016, but they didn’t immediately identify the right technology to pursue.

The two recognized that electrolysis was a promising way to make ethylene and continued to study the process, eventually landing at Stanford University in 2019. But their lab work came to an abrupt halt with COVID-19-related lockdowns. As awful as the pandemic was, Wakerley says, it gave them time to concentrate on Dioxycle: its technology, its goals, even its name, which is a portmanteau of dioxide and recycle.

By the end of 2020, Lamaison and Wakerley had left Stanford to set up shop at a lab in Bordeaux, France. “It was called a lab; it was more like a garage,” Wakerley says.

In 2021, Lamaison and Wakerley were named to the first cohort of Breakthrough Energy Fellows—a program that supports innovators working on clean energy. And in 2023, Dioxycle raised $17 million in series A funding from some of the most important venture capital firms in the cleantech business, including Breakthrough Energy’s venture arm, Lowercarbon Capital, and Gigascale Capital.

Dioxycle faces competition from companies working to electrify crackers, although that ethylene would still require fossil fuel raw materials. Other firms are looking to make ethylene by dehydrating bioethanol, but Wakerley says that technology isn’t as efficient as the electrolyzer.

The chemical transformation that Dioxycle’s electrolyzer performs was first reported in the 1980s by Yoshio Hori and coworkers at Chiba University. The earliest versions of the device were smaller than a postage stamp. Now the electrolyzer is the size of a small car.

Dioxycle plans to begin producing ethylene with an industrial-scale electrolyzer in the next 12 months. If successful, it will demonstrate that the company’s technology can make a dent in the $200 billion-per-year ethylene market.

Wakerley says slashing carbon emissions of one of the key building blocks used to make everyday products will be a huge step toward a more sustainable economy. “We need people to understand that their carbon footprint isn’t just their number of planes taken a year or number of miles driven,” he says. “It’s every product around them that came from the plastic or ethylene supply chain.”