Greenhouse gas may slow down global warming

Date: 9 November 2017

Introduction: UAntwerp researchers use plasma to convert CO2 into valuable substances.

The earth is warming up, and massive CO2 emissions are the main culprit. But scientists from the University of Antwerp have now developed a technology that can convert harmful greenhouse gas into valuable substances such as basic chemicals. Their secret? Plasma!

Global warming remains a hot topic. Politicians can’t stop talking about it: how much further can we let the average temperature rise, and should we introduce a CO2 tax? On the other side of the Atlantic, President Trump has also taken ‘action’ by withdrawing the USA from the Paris climate agreement.

Scientists from all over the world are now looking for solutions. At the University of Antwerp, Prof. Annemie Bogaerts and Dr Ramses Snoeckx (Department of Chemistry) have recently developed a technology that converts CO2, one of the main causes of the greenhouse effect, into valuable substances.

Sun and lightning

“We do that with plasmas”, explains Bogaerts, who leads the PLASMANT research group. Plasma is the fourth state of matter, along with solid, liquid and gas. This state occurs as gas molecules break down into charged particles (ions and electrons) when energy is added. The sun is a plasma, as are weather phenomena such as lightning and the northern lights.

“Today, we mainly use plasma to mass-produce computer chips”, says Bogaerts. “The plasma TV is another recent example. But that same technology is also useful for converting CO2.”

‘The Bigger Picture II’ Dimitri De Waele, digitally altered watercolour on paper © 2017

The plasma is created by applying an electrical voltage across two electrodes. When the voltage is high enough, a spark is created between the electrodes, just like in a short circuit or lightning strike. “In practice, it boils down to us creating little lightning bolts in our reactor”, says Snoeckx, who wrote his PhD on the subject. “These bolts first split the gas molecules into very reactive particles, after which they collide with each other again and form new products.”

Chemical industry

After the ‘plasma treatment’, the CO2 can be processed along with a molecule containing hydrogen (such as water, hydrogen gas, methane or glycerol) and turned into products that can serve as basic chemicals and/or fuels (such as methanol, formaldehyde, ethanol, formic acid, propane and butane). Snoeckx: “This is extremely useful in the chemical industry, for example. CO2 that has already been emitted is converted, preventing further global warming, and carbonaceous products are also created, which would otherwise have to be extracted from oil.”

Snoeckx and Bogaerts published their research in the leading journal Chemical Society Reviews. Scientists are convinced that plasma will go on to play an important role in the future. “Plasmas have unique qualities. For instance, they can convert CO2 at room temperature. The reactors are easily scalable, from small applications to large industrial installations, without the need for expensive rare-earth metals. It is also a very flexible process in terms of location, operation and energy sources.”

“In the next ten years, plasmas will be able to alleviate current climate problems. They offer an ecologically and economically viable solution by producing a wide variety of valuable chemicals from CO2. In other words, we see plasmas not only as lightning and the northern lights, but also as the light at the end of the tunnel.”