Gallium could turn CO2 into usable carbon – UNSW researchers

Engineers from UNSW have helped to discover a cheap new way to capture and convert CO2 greenhouse emissions into a useful, solid carbon form using liquid metal.

The process can be done at room temperature and uses liquid gallium to convert the carbon dioxide into oxygen and a solid carbon product that can later be used in batteries, construction or aircraft manufacturing.

A team from the School of Chemical Engineering, led by Professor Kourosh Kalantar-Zadeh, worked in collaboration with researchers at University of California, Los Angeles (UCLA), North Carolina State University, RMIT, University of Melbourne, Queensland University of Technology, and the Australian Synchrotron (ANSTO).

Their findings have been published in the Advanced Materials journal.

A paper author Junma Tang said: “We see very strong industrial applications with regards to decarbonisation. This technology offers an unprecedent process for capturing and converting CO2 at an exceptionally competitive cost.

“The applications could be in cars to convert polluting exhaust gases, or even at a much larger scale at industrial sites where CO2 emissions could be immediately captured and processed using this technology.

“We have already scaled this system up to two-and-a-half litres dimensions, which can deal with around 0.1 litre of CO2 per minute. And we’ve tested that running continuously for a whole month and the efficiency of the system did not degrade.”

The newly discovered process dissolves captured CO2 gas into a solvent around nanoparticles of gallium, which exist in liquid state above 30°C.

The reactor also contains nano-sized solid silver rods that are the key to generating the triboelectrochemical reactions that take place once mechanical energy such as stirring/mixing is introduced.

A triboelectrochemical reaction occurs in solid–liquid interfaces due to friction between the two surfaces, with an electric field also created that sparks a chemical reaction.

The reactions break the carbon dioxide into oxygen gas, as well as carbonaceous sheets which ‘float’ to the surface of the container due to differences in density and can therefore be easily extracted.

Picture: UNSW

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