A new method of carbon-capture will pave the way for a paradigm shift toward more sustainable, cost-effective CO2 capture solutions.

Postdoc Aleksa Petrovic, alongside postdoc Rodrigo Jose da Silva Lima and colleagues from Professor & CORC PI Jiwoong Lee’s group at KU have found a novel way to harness ‘chain-melting’ in nonporous crystals to effectively capture and easily release CO₂.

“Our findings go beyond improving CO₂ capture. They show that CO₂ can actively trigger changes in a material’s crystal structure - a feature we can now use as a design tool. This opens the door to applying our concept in many different settings and with a wide range of organic materials,” Aleksa Petrovic says.

The article has been published in Nature Communications, and it provides an important and groundbreaking alternative to traditional, state-of-the-art carbon capture methods.

Shapeshifting as a design opens up new possibilities

The researchers based their hydrophobic organic crystals on monoethanolamine (MEA) – a common substance in CO₂-capture field.

Using the monoalkylated monoethanolamine, C10-MEA, they made a crystal that rearranges itself in a fast solid-to-solid phase transition when exposed to CO₂. The actual crystal remains solid but changes its internal structure.

This rearrangement allows CO₂ to penetrate the solid and react with all amine groups, maximizing CO₂ uptake.

When conditions change – i.e. temperature - the material reverses the process and releases CO₂ easily, returning to the original crystal form. Thus, the crystal can be reused several times without degrading.

“Our process requires less energy to both capture and release CO₂ than traditional methods while also being very simple to set up, which really is the key to making carbon capture possible,” Aleksa Petrovic says.

Capturing CO₂ usually relies on materials full of tiny pores, that are very effective at capturing gasses_, but these materials are not selective to CO₂ and demand high amounts of energy to release the captured gas again – typically via heating to temperatures well above 100º Celsius.

However, the reversible chain-melting process works at temperatures as low as 65º Celsius while also using CO₂ itself as a stripping gas, which can provide pure, undiluted CO₂ stream as a product.

Going forward, the next steps focus on achieving the scalability of the technology, while working together with engineers to also examine the design and use-cases of the crystals in different settings.