Methane usually gets talked about as a problem. This time, researchers in Austria say they found a new way to make it.
Vienna University of Technology reported that scientists from the school and the University of Innsbruck found an unexpected route for producing methane in a climate-neutral way. The method uses electricity with water and previously captured carbon dioxide to assemble the fuel.
Professor Günther Rupprechter said the project aimed to develop a streamlined system that could handle both starting materials in a single process.
“For us in the [Materials for Energy Conversion and Storage] research cluster, it was clear that it would be much more elegant to develop a process that accomplishes two things at the same time: first, splitting carbon dioxide to provide carbon, and second, splitting water to simultaneously provide ‘green’ hydrogen,” he said.
Working with nickel on yttria-stabilized zirconia, the researchers found that zirconia does more than move oxygen ions.
First author Christoph Thurner explained: “When we apply an electric voltage, carbon is initially deposited on the nickel atoms, that was what we expected. But part of this carbon then migrates further onto the zirconia surface, where a reactive carbon-zirconium compound is formed. As soon as small amounts of water vapor come into contact with this compound, it reacts again, and methane is formed.”
The researchers said the mechanism was not what they expected. They called the finding “a surprise.”
Methane is a heat-trapping gas in the atmosphere, but it is also a major industrial fuel. Researchers said a process that makes methane from captured carbon dioxide, water and renewable electricity could offer a lower-pollution option while also storing surplus clean energy for later use.
They said the approach may be especially useful when solar generation overshoots demand and photovoltaics produce more electricity than is needed. In that case, surplus power could be stored by converting it into fuel instead of wasting it.
“The idea of converting carbon dioxide into product gases is not new,” Rupprechter said. “Carbon dioxide can be split and then reacted with hydrogen. However, the question then is: Where does the hydrogen come from?”
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