Removing and transforming CO2 from the atmosphere has been the subject of discussion for more than a decade but it has not been until these last few years that proposals are being put forward that can really be carried out.
Atmospheric carbon is one of the biggest environmental problems.
We need to fix it cheaply and in a scalable way, something that is capable of extracting enough carbon from the atmosphere to make a difference. We could have found the remedy.
Now, a team of scientists, led by a team from RMIT University in Melbourne, Australia, has used liquid metals to convert carbon dioxide back to solid carbon, in a first global advance that could transform our approach to capture and the storage of coal.
Rewinding the carbon cycle in greenhouse gases and finding a way to get them back into the ground has been the great dream of scientists since we discovered the threat of global warming.
Since then, we have devised a long list of remedies: from growing and burying biomass to pumping the gas into underground reservoirs and speeding up chemical reactions that can turn CO2 into a less volatile material.
Some are cheap, but relatively slow. Others just don’t offer enough of an incentive for the big polluters to pay attention.
Old problems, new solutions
In recent years, great strides have been made to arrive at a suitable environmental solution.
Not only is the new technique developed in Australia relatively fast, it also doesn’t require large amounts of pressure (or complicated chemical reactions) to convert carbon dioxide into a solid form of carbon.
The trick is in the nanoparticles of the metal cerium, which plays a leading role in an electrochemical reaction that extracts oxygen from carbon dioxide at a mild voltage. The suspension of the nanoparticles in the form of a liquid metal alloy prevents the accumulation of solidified carbon on the cerium, which improves the efficiency of the process. Better yet, using the metallic gallium as a solvent means that the entire process can take place at room temperature, given the element’s remarkably low melting point.
“To date, CO2 has only become a solid at extremely high temperatures, which makes it industrially unviable,” says Torben Daeneke, co-author of the work.
Thus, to achieve this conversion of CO2, the researchers have designed a catalyst from a non-toxic gallium alloy that activates the process and makes it extremely efficient as a conductor of electrical signals.
“By using liquid metals as a catalyst, we have shown that it is possible to convert gas to carbon at room temperature, in a process that is efficient and scalable.”
An advantage over other similar methods
It is not necessarily intended for the ground.
“An additional benefit of the process is that the carbon can hold the electrical charge, becoming a supercapacitor, so it could potentially be used as a component in future vehicles,” says lead study author Dorna Esrafilzadeh. “The process also produces synthetic fuel as a by-product, which could also have industrial applications.”
Carbon-based products, such as graphene, have the potential to revolutionize the future of electronics, not only as a supercapacitor but also as a superconductor.
Daeneke concludes: “While more research is needed, it is a crucial first step in delivering robust carbon storage .”
Referencia: Room temperature CO2 reduction to solid carbonspecies on liquid metals featuring atomically thin ceria interfaces, Nature Communications (2019). DOI: 10.1038/s41467-019-08824-8 , https://www.nature.com/articles/s41467-019-08824-8
Crédito imagen: RMIT University
