Australian scientists have unlocked a new and more “efficient” way to turn carbon dioxide back into solid coal, in a world-first breakthrough that could combat rising greenhouse gas levels.
Researchers at Melbourne’s RMIT University have used liquid metals to convert CO2 from a gas to a solid at room temperature.
The technique has potential to “safely and permanently” remove CO2 from the atmosphere, according to the new study published in the journal Nature Communications.
Carbon technologies have previously tended to focus on compressing CO2 into a liquid form, transporting it to a suitable site and injecting it underground.
The use of underground injections to capture and store carbon is not economically viable and sparks fears of an environmental catastrophe due to possible leaks from the storage site.
However, the new technique transforms CO2 into solid flakes of carbon, similar to coal, which can be stored more easily and securely.
Carbon dioxide is dissolved into a beaker containing an electrolyte liquid, then a small amount of the liquid metal catalyst is added, which is then charged with an electrical current.
The electrical current serves as a catalyst to slowly converts the CO2 into solid flakes of carbon.
This is a “crucial first step” to developing a more sustainable approach to converting CO2 into a solid, RMIT researcher Dr Torben Daeneke said, noting that more research is required cement the process.
He described the process as “efficient and scalable”.
“While we can’t literally turn back time, turning carbon dioxide back into coal and burying it back in the ground is a bit like rewinding the emissions clock.
“To date, CO2 has only been converted into a solid at extremely high temperatures, making it industrially unviable,” Dr Daeneke said.
The study’s lead author, Dr Dorna Esrafilzadeh, said the carbon produced could also be used as an electrode.
“A side benefit of the process is that the carbon can hold electrical charge, becoming a supercapacitor, so it could potentially be used as a component in future vehicles,” she said.
“The process also produces synthetic fuel as a by-product, which could also have industrial applications.”
The study was completed in collaboration with researchers from Germany (University of Munster), China (Nanjing University of Aeronautics and Astronautics), the US (North Carolina State University) and Australia (UNSW, University of Wollongong, Monash University, QUT).