It has been agreed that if we want to fix the climate change, then it is not enough to cut back on carbon dioxide emissions. Instead, we need to remove carbon dioxide from the air as well. The strategy of capturing carbon from the air and sequestering it is becoming more and more viable. Keeping in this spirit, a team of scientists has come up with a new method that is aimed at transforming the CO2 back to solid coal that can then be buried again or used for electrical components.
Generally, the captured carbon can then be used for making concrete, fizzy drinks, or fuels. When it comes to storing CO2, the gas is compressed into a liquid form or bonded with water. Once that has been done, it is injected deep underground. Once underground, it interacts with basalt rock and solidifies into a carbonate mineral in about two years. However, an MIT investigation revealed that only the top layer was becoming solid leaving huge pockets of gas with the potential problem of the gas leaking into the atmosphere again thus undoing all of the hard work. The new study that has been carried out by researchers from Australia, China, US, and Germany was aimed at developing a way for the solidification of carbon before it gets stashed underground.
The new method makes use of a liquid metal catalyst composed of a gallium alloy and cerium. The liquid metal catalyst was developed by the team. The CO2 gas is first dissolved into a beaker that contains an electrolyte liquid. A small amount of the liquid metal catalyst is then added to the mix. Upon introducing an electrical current, the catalyst makes the surface of the mixture chemically active. The surface then transforms the CO2 into solid flakes of carbon slowly.
The catalyst was designed to be a fantastic conductor of electricity and efficient when it comes to performing the reaction. Since the catalyst is liquid, the carbon flakes do not stick to it as is the case with a solid catalyst. This enables the team to run it longer without the whole contraption becoming fouled up. According to researchers, this process can be carried out at room temperature unlike other carbon conversion processes thus making it very less energy intensive.
Torben Daeneke, an author of the study, said, ‘To date, CO2 has only been converted into a solid at extremely high temperatures, making it industrially unviable. 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. While more research needs to be done, it’s a crucial first step to delivering solid storage of carbon.’
Dorna Esrafilzadeh, the lead author of the study, said, ‘A side benefit of the process is that the carbon can hold an electrical charge, becoming a supercapacitor, so it could potentially be used as a component in future vehicles. The process also produces synthetic fuel as a by-product, which could also have industrial applications.’
The research has been published in the journal, Nature Communications.