New electrochemical system converts captured carbon dioxide into ethylene

The increasing global demand for energy has led to faster consumption of fossil fuels, which has led to increased human activity CO2 انبعاثات emissions, causing critical environmental problems. Despite the continuous progress in increasing the use of renewable energy sources such as solar energy, wind energy and Hydroelectricity To reduce fossil fuel consumption, these resources still meet a fraction of current energy requirements. Thus, there is an urgent need to develop sustainable alternatives to mitigate the concentration of anthropogenic carbon dioxide in the atmosphere.

Now, engineers at the University of Illinois at Chicago (UIC) have discovered a way to convert 100% of the carbon dioxide captured from industrial exhaust into ethylene, a building block for plastic products.

For years, scientists have been exploring the possibility of transmutation Carbon dioxide captured into such a useful substance as ethylene, one of the main precursors of plastic. But the UIC researchers claim their approach is the first to achieve nearly 100% use of carbon dioxide to produce hydrocarbons.

The UIC team’s system uses electrolysis to convert captured carbon dioxide gas into high-purity ethylene, with other carbon fuels and oxygen as by-products. Researchers develop a water electrochemical cell that could make conversion more efficient. An electric current passes through the cell, half of which is filled with captured carbon dioxide while the other half contains an aqueous solution.

Abstract illustration of atoms passing through water and an electrified membrane under bright sunlight. Illustration: Minish Singh.

The electrocatalyst pulls the charged hydrogen atoms from the water molecules to the other half of the unit separated by a membrane, where they combine with the charged carbon atoms in carbon dioxide, forming C2H4 – ethylene. The process can convert up to 6 metric tons of carbon dioxide into 1 metric ton of ethylene, Recycling Almost all of the carbon dioxide is captured.

Usually, ethylene is made in a process called steam cracking which requires huge amounts of heat. Cracking generates about 1.5 metric tons of carbon emissions for every ton of ethylene produced. But the team says that the use of Renewable energy The new system’s operating sources could make the process carbon negative.

According to lead researcher Meenesh Singh, his team’s approach goes beyond the net-zero goal of other carbon capture and conversion technologies by reducing total carbon dioxide output from the industry. “It’s a net negative” he is He said. “For every 1 ton of ethylene produced, you take in 6 tons of carbon dioxide from stationary sources that would otherwise be released into the atmosphere.”

In addition, UIC scientists have been able to produce other carbon-rich products useful for industry through the electrolysis approach. They have also achieved a very high efficiency in solar energy conversion, converting 10% of the energy from Solar Panels Direct to carbon product production. This is well above the most recent benchmark of 2%. For all the ethylene it produces, Solar energy The conversion efficiency was about 4%, almost the same as the rate of photosynthesis.

Ethylene is used not only to make plastic products for packaging, agriculturalthe automotive industries but also for the production of chemicals used in antifreeze, medical sterilizers and vinyl siding for homes.

Journal reference:

  1. Aditya Prajapati, Nishithan C. Kani, Joseph A. Gauthier, Rohan Sartape, Jiahan Xie, Ivan Bessa, Michael T. Galante, Samuel L. Lung, Marcus H.S. Andrade, Robert T. Somich, Marcus V. Rebouças, Gus T. Hutras , Natalia Deniz, Minish R. Singh. Carbon dioxide-free high-purity ethylene electrolyte adsorption of carbon dioxide 4% from solar to ethylene and 10% from solar to carbon. The Physical Science of Cell Reports, 2022; DOI: 10.1016 / j.xcrp.2022.01053