Bottled lightning makes a cleaner fuel

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Bottled lightning makes a cleaner fuel

Bursts of plasma convert methane into methanol without high heat and pressures

EMBARGOED UNTIL 8 A.M. EDT (U.S.) ON WEDNESDAY, APRIL 15, 2026

• Methanol production consumes enormous amounts of energy and generates significant carbon dioxide
• New process uses tiny bursts of underwater plasma to convert methane to methanol in just one step
• Plasma is a rare form of matter on Earth but makes up 99% of the observable universe
• If scaled, new system could convert methane into fuels at the source of leaks

EVANSTON, Ill. --- Northwestern University chemists have discovered a new way to turn natural gas into liquid fuel - and it's lightning in a bottle.

By harnessing tiny bursts of plasma - or mini "lightning bolts" - in glass tubes submerged in water, the team has successfully converted methane directly into methanol in a single step. Methanol is a versatile, high-demand industrial chemical used to make many products people use every day. It also is commonly used as an industrial solvent and is gaining attention as a cleaner-burning fuel for ships and industrial boilers.

The method bypasses the extreme heat and high pressures required for current industrial processes, which blast apart methane and rebuild it as methanol in a multi-step process. While the current method is reliable, it's energy intensive and emits millions of tons of carbon dioxide per year globally.

Using just electricity, water and a copper-oxide catalyst, the new process could offer a cleaner, electrified path to producing one of the world's most widely used chemical building blocks.

The study will be published on Wednesday (April 15) in the Journal of the American Chemical Society.

"We're using pulses of high-voltage electricity," said Northwestern's Dayne Swearer, the study's corresponding author. "If the electrical potential is high enough, lightning bolts form inside of our reactor the way they do during a summer thunderstorm. We're taking advantage of that chemistry to break methane's bonds without heating the entire system to extreme temperatures."

Swearer is an assistant professor of chemistry at Northwestern's Weinberg College of Arts and Sciences and of chemical and biological engineering at Northwestern's McCormick School of Engineering. He also is a member of the International Institute of Nanotechnology, Paula M. Trienens Institute for Sustainability and Energy and the Northwestern-Argonne Institute for Scientific and Engineering Excellence.

Ripping and rebuilding

One of the world's most used commodity chemicals, methanol is a key ingredient in plastics, paints and adhesives. More recently, researchers have explored methanol as a promising liquid fuel because its combustion produces lower sulfur emissions and particulate pollution than gasoline and diesel.

Currently, industry generates methanol through a multi-step process, starting with steam reforming. First, methane is reacted with steam at temperatures exceeding 800 degrees Celsius to break it into carbon monoxide and hydrogen. Then, those gases are recombined under extremely high pressures - 200 to 300 times standard atmospheric pressure - to form methanol. Tearing methane apart and rebuilding it consumes an enormous amount of heat and inherently generates carbon dioxide along the way.

"The extreme temperatures are needed to break the unreactive chemical bonds between carbon and hydrogen in methane," Swearer said. "Then, you must use high pressure to squeeze all those molecules together onto the catalyst in order to make the methanol molecule. It works, but it's not the most straightforward path to making methanol from methane."

Replacing heat with plasma

While researchers have long sought a more energy-efficient, single-step solution, they have struggled to overcome two challenges. Methane is unusually stable and difficult to break apart, requiring extreme reaction conditions. Then, once methanol is formed, it continues to react, rapidly degrading into carbon dioxide. So, the challenge lies in not just starting the reaction but stopping it at exactly the right moment.

To overcome these issues, Swearer and his team turned to plasma, a highly energized state of matter filled with fast-moving, "hot" electrons. Most people might be familiar with plasma as the type of matter that makes up the sun or lightning bolts. Those are examples of hot plasmas. Swearer's group works primarily with cold plasmas, in which the gas molecules' temperature is closer to room temperature, but the electrons are selectively heated to temperatures that can exceed tens of thousands of degrees.

"More than 99% of the observable universe is comprised of plasma," said James Ho, a Ph.D. candidate in Swearer's lab and the study's first author. "But even though it's ubiquitous, it really is an untapped resource in the field of chemistry. The reason we use cold plasmas is because we can produce them at low temperatures and normal atmospheric pressure conditions."

For the new single-step process, Ho built a plasma "bubble reactor," which is essentially a porous glass tube coated with a copper oxide catalyst. Then, the team flowed methane gas through the tube while applying electrical pulses. The electricity transformed the methane gas into plasma, splitting methane and water into highly reactive fragments. Those fragments then recombined to form methanol, which immediately dissolves into the surrounding water. That rapid "quenching" stopped the chemical reaction at the right moment, preventing the methane from decomposing into carbon dioxide.

Enhancing with argon

To further enhance the process, the team diluted methane with argon, which is typically an inert noble gas. But, after ionizing argon in the plasma, the chemists discovered it became an active and reactive participant in the chemical process, increasing electron density within the plasma and reducing unwanted byproducts.

Under the optimized conditions with argon present, the system demonstrated 96.8% methanol selectivity in the liquid mixture. In other words, of all the liquid products formed in the process, it was mostly methanol. And, of all the products formed - both gas and liquid - about 57% ended up as methanol.

"We also ended up with ethylene, which is a precursor to plastic production, and hydrogen gas, which is an important commodity chemical and a zero-carbon fuel in its own right," Swearer said. "So, we took methane, which is a very abundant gas, and turned it into methanol along with ethylene, hydrogen and a bit of propane. These are all intrinsically more valuable products."

Toward smaller, distributed systems

If scaled, the plasma-driven system could enable smaller, distributed facilities that use electricity to convert methane into liquid fuels.

"We could treat stranded resources, like leaky well heads that naturally emit methane into the environment," Swearer said. "Right now, the way to deal with leaked methane is to light it on fire to turn it into carbon dioxide, which warms the climate less than methane but is still clearly a problem. Instead, we could take a smaller scale reactor to the place that's leaking methane and turn it into a transportable liquid fuel."

Next, Swearer and his team plan to optimize the system further and explore ways to efficiently recover and separate methanol as a purified product.

The study, "Direct partial oxidation of methane at plasma-catalyst-liquid interfaces," was supported by the U.S. Department of Energy (award number DE-SC0024540), the U.S. Army DEVCOM ARL Army Research Office (award number W911NF-25-1-0026) and the David and Lucille Packard Foundation.

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Experiment image

Please credit image to Dayne Swearer/Northwestern University

Dayne Swearer

Corresponding author

Assistant professor of chemistry and chemical and biological engineering

• [email protected]