Scientists discover the first molecule of its kind that absorbs greenhouse gases: ScienceAlert

A “cage of cages,” scientists have described a new type of porous material that is unique in its molecular structure and could be used to trap carbon dioxide and another, more potent greenhouse gas.

The material, synthesized in the lab by researchers in the UK and China, is made in two steps, using reactions to assemble triangular prism building blocks into larger, more symmetrical tetrahedral cages – creating the first molecular structure of its kind, the team claims.

The resulting material, with its abundance of polar molecules, attracts and traps greenhouse gases such as carbon dioxide (CO).₂) with strong affinity. It also demonstrated excellent stability in water, which would be crucial for its use in carbon sequestration in industrial environments from wet or humid gas streams.

“This is an exciting discovery,” says Marc Little, materials scientist at Heriot-Watt University in Edinburgh and lead author of the study, “because we need new porous materials to solve society’s biggest challenges, such as trapping and Storing greenhouse gases.”

Although it has not been tested at scale, laboratory experiments showed that the new cage-like material also had high absorption of sulfur hexafluoride (SF).₆), which, according to the Intergovernmental Panel on Climate Change, is the most powerful greenhouse gas.

Where CO₂ Remains in the atmosphere for 5-200 years, SF₆ may remain between 800 and 3,200 years. So even though SF₆ The concentrations in the atmosphere are much lower, giving SF its extremely long lifespan₆ a global warming potential around 23,500 times that of CO₂ compared to over 100 years.

Remove large amounts of SF₆ and Co₂ We must take urgent action to curb climate change by removing them from the atmosphere or preventing them from entering the atmosphere in the first place.

Researchers estimate that we need to extract around 20 billion tons of CO₂ every year to compensate for our CO2 emissions, which are only trending upwards.

So far, CO2 removal strategies are removing about 2 billion tons per year, but it is mostly trees and soils that are doing their part. Only about 0.1 percent of carbon removal, about 2.3 million tons per year, is thanks to new technologies such as direct air capture, which uses porous materials to absorb CO₂ from the air.

Researchers are busy developing new materials to improve direct air capture and make it more efficient and less energy intensive. This new material could be another option. But to avert the worst effects of climate change, we must reduce greenhouse gas emissions faster than these new technologies currently can.

Nevertheless, we must tackle this global problem with all our might. However, it was not easy to produce a material with such high structural complexity, even if the precursor molecules technically self-assemble.

This strategy is called supramolecular self-assembly. It can create chemically interlocking structures from simpler building blocks, but it requires some fine-tuning because “the best reaction conditions are often not intuitively obvious,” Little and colleagues explain in their published paper.

The more complex the final molecule, the more difficult it will be to synthesize and more molecular “mess” can occur in these reactions.

To get to grips with these otherwise invisible molecular interactions, the researchers used simulations to predict how their starter molecules would assemble into this new type of porous material. They took into account the geometry of potential precursor molecules as well as the chemical stability and stiffness of the final product.

Aside from its potential to absorb greenhouse gases, the researchers suggest their new material could also be used to remove other toxic fumes from the air, such as volatile organic compounds, which easily form vapors or gases from surfaces, including the interiors of new cars.

“We see this study as an important step towards developing such applications in the future,” says Little.

The study was published in Nature Synthesis.