As far as environmental supervillains go, atmospheric carbon is the kingpin of crime. And just like in the comic books, every time we think we have a way to lock it up for good, it gets away from us.
What we need is something cheap. Scalable. Something that can have a hope of ripping enough carbon from the atmosphere to actually make a difference. Well, a new technique from scientists in Australia could be what we’ve been looking for.
Researchers from RMIT University in Melbourne have developed technology that can convert carbon dioxide gas into particles of what is essentially pure soot.
Rewinding the carbon cycle on greenhouse gases and finding a way to return them to the ground has been a dream of scientists ever since we discovered the threat of global warming.
We’ve come up with a long list of ways we can sequester carbon, from growing and burying biomass to pumping the gas into reservoirs underground to speeding up the chemical reactions that can turn CO2 into a less volatile material.
The end result is we really shouldn’t pin our hopes on negative emissions solving our carbon crisis.
Still, headway has been made in recent years, making us optimistic we could be getting closer to an environmental solution.
The new technique developed in Australia isn’t just relatively quick, it also doesn’t require huge amounts of pressure (or complicated chemical reactions) to turn carbon dioxide into a solid form that can be locked away again.
The trick is in nanoparticles of the metal cerium, which has a starring role in an electrochemical reaction that rips away the oxygen from carbon dioxide at a gentle voltage.
Suspending the nanoparticles in the form of a liquid metal alloy prevents a build-up of the solidified carbon over the cerium, enhancing the efficiency of the process.
Better still, using the metal gallium as a solvent means the whole process can take place at room temperature, given the element’s remarkably low melting point.
“To date, CO2 has only been converted into a solid at extremely high temperatures, making it industrially unviable,” says RMIT physical chemist Torben Daeneke.
“By using liquid metals as a catalyst, we’ve shown it’s possible to turn the gas back into carbon at room temperature, in a process that’s efficient and scalable.”
It’s that scalability that just might see it make a dent in emissions. But there’s another outcome that could also give this process an edge over other similar methods; its product isn’t necessarily destined for the ground.
“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,” says lead author and engineer Dorna Esrafilzadeh.
“The process also produces synthetic fuel as a by-product, which could also have industrial applications.”
Even if only a fraction of the hype is realised, a materials industry based on carbon could be worth big dollars in the future.
It’s quickly becoming clear that economic incentives pose as much of a problem in fixing our environmental concerns as any technological challenge.
Whether it’s pulling plastics from our oceans or carbon dioxide from the atmosphere, the road to success needs to be paved in gold.
“While more research needs to be done, it’s a crucial first step to delivering solid storage of carbon,” says Daeneke.
This research was published in Nature Communications.