High-pressure electrolysis sustainably converts captured CO₂ into industrial-grade ethylene

Researchers at King Abdullah University of Science and Technology have unveiled a breakthrough system that could change the way we think about carbon emissions. Published in Nature Catalysis the researchers outline a system for converting captured carbon dioxide (CO₂) into industrial-grade ethylene, a commodity chemical essential to plastics, textiles, and construction. The work shows a direct path to transforming greenhouse gas emissions into valuable chemical products.

In addition to the environmental benefits, lead researcher Assistant Professor Xu Lu said key efficiencies in the system create an opportunity to turn the otherwise costly process of capturing CO₂ into a profit.

“We designed and tested the system under realistic industrial conditions using captured, high-pressure CO₂,” he said. “Our results show captured carbon can be valorized into a valuable product with real economic potential.”

Captured CO₂ can be processed in many ways. However, to produce ethylene, whose global market exceeds $200 billion per year, electrolysis is particularly promising, as it can be powered by renewable electricity and operate in milder conditions than other capture techniques.

Lu led a research team that designed a high-pressure electrolyzer to convert O₂ with water into ethylene. High-pressure CO₂ is the output of commercial carbon capture systems, but little research has been done on the role of pressure when electrochemically converting CO₂ into a valuable commodity. The KAUST breakthrough, Lu said, is the first to show that using industrial CO₂ pressures can dramatically improve electrolysis performance and stability.

In contrast, many prior systems require depressurizing or repressurizing steps, which demands high amounts of energy, and costly purification of the ethylene due to the output of a mixed product. Lu added that the KAUST system reduces the energy cost of producing ethylene by 0.8 gigajoules per metric ton compared with existing electrolysis systems, which is enough energy to power an average home for a week.

An economic analysis shows the KAUST process can make ethylene at $1,240 per ton, which is about the same as today’s market price. However, unlike standard ethylene production methods, which are energy- and carbon-intensive, the KAUST process uses CO₂ and could operate on renewable electricity. With system optimization, costs may fall further and turn carbon capture from a cost burden into a profit opportunity.

Professor William Roberts also contributed to the study.