Australian ‘alchemy’ turns carbon dioxide into coal

Australian scientists ‘rewind emissions clock’ in a breakthrough that could transform thoughts on carbon sequestration.

Australian researchers have discovered a way to ‘turn carbon dioxide into coal’. Picture: File

In a feat of modern alchemy, Australian scientists have found a way to “rewind the emissions clock” by turning carbon dioxide into coal.

In a paper in the journalNature Communications , researchers from Melbourne’s RMIT detail a low-cost method that could transform the way the world thinks on carbon sequestration.

The major breakthrough is that the process to generate hard carbon from CO2 can be done at room temperature. This reduces the energy required and the cost.

Lead author Dorna Esrafilzadeh said the research showed that by applying the right catalyst, CO2 could be converted to carbonaceous materials at room temperature and buried in the ground.

Describing the breakthrough as turning CO2 to coal was “a fair portrayal”, she said.

Research scientist Torben Daeneke said: “While we can’t literally turn back time, turning carbon dioxide into coal and burying it back in the ground is a bit like rewinding the emissions clock.”

The process offers a new way to solve the problem of carbon dioxide emissions from cement, steel-making, and gas and coal electricity production. The carbon product can be used to produce more energy or safely buried as an alternative to pumping liquid CO2 deep underground.

Schematic of the catalytic process: the proposed process is based on operando Raman measurements. It includes pre-catalytic reactions and the catalytic cycle for the CO2 reduction to amorphous carbon sheets.

“The fact the conversion happens at room temperature makes this technique efficient and viable for industrial use,” Dr Esrafilzadeh told The Australian. “In previous reports, CO2 has only been converted into solid carbon at super-high temperatures, making it industrially unviable.

“With more research and development, it is practical to eventually convert CO2 out of the ambient air.”

Researchers developed a liquid metal catalyst with specific surface properties, making it extremely ­efficient at conducting electricity, while chemically activating the surface. Detailing the process, a statement on the research said CO2 was dissolved in a beaker with an electrolyte liquid and a small amount of the liquid metal, which was then charged with an electric current.

The CO2 slowly converts into solid flakes of carbon, which are naturally detached from the liquid metal surface, allowing the continuous production of carbonaceous solid.

“Overall, this liquid metal en­abled electrocatalytic process at room temperature may result in a viable negative emission technology,” the paper said.

“Negative emission technologies that convert emitted anthro­pogenic CO2 into solid products that are suitable for indefinite storage are expected to play a crucial role in stabilising the global climate, once the current transition of the world’s economy to carbon-neutral energy sources has been completed.”