The breakthrough in carbon recycling converts 100% of CO2 into ethylene

The researchers’ new system at the University of Illinois at Chicago uses electrolysis to transform captured carbon dioxide gas into high-purity ethylene, with other carbon and oxygen-based fuels as by-products.

Their reporting paper was published in Cell Reports Physical Science.

The discovery offers a way to convert 100% of the carbon dioxide captured by industrial waste into ethylene, a building block for plastics and the main ethylene-based product.

While researchers have been exploring the possibility of converting carbon dioxide to ethylene for more than a decade, the UIC team’s approach is the first to reach almost 100% use of carbon dioxide to produce hydrocarbons

The process can convert up to 6 tons of carbon dioxide to 1 ton of ethylene, recycling almost all the carbon dioxide captured. Since the system runs on electricity, the use of renewable energy can make the process carbon negative.

According to Singh, his team’s approach exceeds the net zero carbon emissions goal of other carbon capture and conversion technologies, effectively reducing the total carbon dioxide production from industry. “It’s a net negative,” he said. “For every 1 ton of ethylene produced, you are taking 6 tons of CO2 from point sources that would otherwise be released into the atmosphere.”


Previous attempts to convert carbon dioxide into ethylene relied on reactors that produce ethylene within the source carbon dioxide emission stream. In these cases, only 10% of CO2 emissions typically convert to ethylene. Ethylene must subsequently be separated from carbon dioxide in an energy-intensive process that often involves fossil fuel energy.

In the UIC approach, an electric current is passed through a cell, half of which is filled with captured carbon dioxide, the other half with a water-based solution. An electrified catalyst attracts charged hydrogen atoms from the water molecules into the other half of the unit separated by a membrane, where they combine with charged carbon atoms of the carbon dioxide molecules to form ethylene.

Among the world’s manufactured chemicals, ethylene ranks third for carbon emissions after ammonia and cement. Ethylene is used not only to make plastic products for packaging, the agricultural and automotive industries, but also to make chemicals used in antifreeze, medical sterilizers, and vinyl siding for homes.

Ethylene is usually produced in a process called steam cracking which requires huge amounts of heat. Cracking generates about 1.5 tons of carbon emissions per ton of ethylene created. On average, producers produce around 160 million tons of ethylene every year, which translates to over 260 million tons of carbon dioxide emissions worldwide.

In addition to ethylene, UIC scientists have been able to produce other carbon-rich products useful to industry with their approach to electrolysis. They also achieved very high solar energy conversion efficiency, converting 10% of the energy from solar panels directly into producing carbon products. This is well above the state-of-the-art 2% standard. For all ethylene produced, the solar energy conversion efficiency was approximately 4%, approximately the same rate as photosynthesis.

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This is the kind of news that needs to grab the attention of independent oil producers and the coal industry. As the process matures, we may see a gradual shift from fossil fuel sources to a form of current CO2 recycling regulation. The press release is partly driven by CO2 effluent which ranks 3rd in ethylene production. There is much more CO2 available from ammonia, cement, power generation and other large concentrated sources of CO2. While the 4% efficiency rating won’t turn everyone on, keep in mind that 4% is about where nature is satisfied after hundreds of millions of years with great results. The 10% notation from solar panels is impressive and suggests that further improvements may come over time.

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Plastic is an obvious target as the energy input is concentrated and large. But there are other opportunities, and this new technology only requires much greater and broader attention and effort.

Many questions remain. Has the oxygen in the water that has lost its hydrogen just been discharged? So how does it compare to water electrolysis since the released hydrogen is already locked up in a carbon-based gas?

If more products are likely to be on the way, is a selection of light petroleum gases such as methane, propane and butane also possible? So is there a likelihood that liquid alcohols can also arrive? If this technology were to gain development and traction on the market, will the optimal product also trigger the development of fuel cells?

Yes. Great news indeed! Congratulations to the UIC team!

By Brian Westenhaus via New Energy and Fuel

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