Two new studies have contributed to the field of carbon dioxide removal, a potentially vital tool in the fight against climate change. In an article published in the journal Nature Communications, researchers at RMIT University in Melbourne, Australia, have described a technique that converts the greenhouse gas into solid carbon.
The team, led by Dorna Esrafilzadeh, developed a liquid metal electrocatalyst containing nanoparticles of the rare earth metal cerium, which can be used to electrochemically transform gaseous carbon dioxide into a carbonaceous solid when subjected to an electrical current.The most striking feature of the process is that it occurs at a low initial voltage and, crucially, at room temperature – making it relatively economical in terms of both cost and energy consumption. Furthermore, the resulting material has a potential application as a supercapacitor in high-performance batteries.
For direct air capture, less space but more power is needed
Meanwhile, a study by Berlin-based climate research institute MCC, published in the journal Energy & Environmental Science, has concluded that it is more efficient – and will soon be cheaper – to capture carbon dioxide directly from the air than to achieve the same effect indirectly by cultivating biomass. At present, the absorption of carbon dioxide by plants remains the more cost-effective option by a significant margin, besides producing electricity – in contrast to filtration processes, which require large amounts of power themselves.
Nevertheless, “our study shows that direct extraction is becoming a serious alternative for three reasons,” says Felix Creutzig, the coordinator of the project. “First, there are signs of considerable cost-saving technical progress. Second, it is more scalable due to its smaller space requirements.” Biomass cultivation for natural carbon capture requires huge areas of land. Finally, filtration will become increasingly effective as more of the energy used to power the process is obtained from renewable sources, Creutzig explains.