A global collaboration of researchers has used liquid gallium in a cheap process done at room temperature which converts carbon dioxide into oxygen and a high-value solid carbon product, useable in batteries, construction, or aircraft manufacturing.
The results have been published in the journal Advanced Materials, showing potential for the process to be used in a wide variety of ways to substantially reduce greenhouse gas levels.
Led by the University of NSW’s School of Chemical Engineering, the project included researchers from University of California Los Angeles, North Carolina State University, RMIT, University of Melbourne, Queensland University of Technology and the Australian Nuclear Science and Technology Organisation.
Lead author Junma Tang said it showed very strong industrial applications with regards to decarbonisation.
Tang said: “This technology offers an unprecedented process for capturing and converting carbon dioxide 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 carbon dioxide 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 litres of carbon dioxide per minute, and we’ve tested that running continuously for a whole month and the efficiency of the system did not degrade.”
The conversion process dissolves captured carbon dioxide gas into a solvent around nanoparticles of gallium, which exist as a liquid above 30 degrees Celsius.
Nano-sized solid silver rods are also within the reactor, used to generate triboelectrochemical reactions once the solvent is mixed.
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.
This reaction breaks down the carbon dioxide into oxygen gas and carbonaceous sheets, which float to the surface due to its lower density.
Testing demonstrated a 92 per cent efficiency in converting a tonne of carbon dioxide and used just 230 kilowatt hours of energy, equating to an estimated cost of around $100 per tonne of carbon dioxide.
A company to commercialise the research, called LM Plus, was established with support from UNSW and seed investment from Uniseed.
Uniseed investment manager and LM Plus director Paul Butler said this was a very green process, producing a high-value carbonaceous sheet which can be used to make electrodes in batteries or for carbon fibre materials used in high-performance products like aircraft, racing cars, and luxury vehicles.
He continued: “What we are working towards now is to raise funds to build a larger size proof-of-concept for this system to work within a 40-foot container – the size of a truck trailer – that could ultimately help industrial sites immediately capture any carbon dioxide emissions and convert them.”