With plasma, zapping harmful chemicals away
Refrigerants known as hydrofluorocarbons (HFCs) are among the most common and most harmful greenhouse gases, and getting rid of them is complicated. A team of researchers has found an effective and efficient way to break down these chemicals by zapping them with plasma. Portable and accessible, it has the potential to prevent gigatons of harmful emissions from entering the atmosphere. The results are published in ACS Energy Letters.
Why it matters
To give some perspective as to how powerful these gases are, Prof. Lea Winter notes that one tank of the most potent HFCs is equal to the carbon dioxide (CO₂) that would be generated from burning more than 4,000 tanks of gasoline, or about the amount of CO₂ that could be removed by 9,000 trees. “So this is a big issue where we could have a lot of impact,” said Winter, assistant professor of chemical and environmental engineering.
The problem
Currently, HFCs are destroyed at intensive high-temperature facilities. Due to strict permitting and other factors, though, there’s a very limited number of these facilities in the world. Transporting these gases to bring them to a facility is often impractical, and increases the risk that they will leak into the atmosphere en route. Further, transporting HFCs over certain borders is prohibited. This leaves few options to responsibly manage these gases. As a result, waste HFCs are often vented to the atmosphere illegally, especially in more remote locations or in developing countries.
The solution
“We’re using a low-temperature plasma to activate the strong, inert carbon-fluorine bonds in HFCs,” said Winter, who’s leading the research. “These are the same chemical bonds that lead PFAS to be forever chemicals.”
But there are a few challenges, Winter notes. One is that when using plasma on these gases, you run the risk of producing highly toxic hydrofluoric acid. Another is that previous research has shown that using plasma for HFC remediation can be inefficient and generate byproducts.
“We wanted to come up with a way to make the plasma more efficient at degrading the HFCs while also - in an inherently safe process - neutralizing the hydrofluoric acid," she said. They did so by coupling the plasma with a water interface so that the plasma directly discharges to the water (“it’s like little lightning bolts striking a water surface,” Winter says).
“We’re using a low-temperature plasma to activate the strong, inert carbon-fluorine bonds in HFCs ... the same chemical bonds that lead PFAS to be forever chemicals.
Lea Winter
Chemical & Environmental Engineering
Initially, they incorporated water for safety purposes, but found that water and other oxidants actually enhanced the conversion rate of the HFCs. As a result, the system has direct plasma chemistry in the gas phase, plus additional reactions that occur in the liquid to further degrade and defluorinate the HFCs. The process transforms the fluorine in HFCs into fluoride, a stable and negatively charged ion.
“As the fluorine comes off the HFC, it's immediately neutralized as fluoride,” she said. “Instead of making the more harmful hydrofluoric acid, we’re making something that's more like mouthwash.”
In addition to being energy-efficient with a very high conversion rate, the system is portable, allowing it to be potentially used on the sites of cooling equipment and storage tanks. That eliminates the need to transport HFCs over long distances.
Going forward, Winter’s lab will further study the effects of the water-plasma combination.
“In terms of the fundamental science, we want to understand more about how this degradation process happens,” she said. “So we’ll look at the fundamental plasma solution electrochemistry. Those insights can be important for a wide range of applications.”
And with a Constellation Grant from Yale Planetary Solutions, she’s researching ways to scale the system for use in practical applications.
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Published Date
Jan 8, 2026
