Creating carbon nanofibres from carbon dioxide in the air

A team of chemists from the George Washington University claims to have developed a way to economically change atmospheric CO2 from a climate change problem to a valuable commodity. The team's technology is said to convert the greenhouse gas into carbon nanofibres for industrial and consumer products.

The team will present its research at the 250^th National Meeting and Exposition of the American Chemical Society (ACS).

"We have found a way to use atmospheric CO₂ to produce high-yield carbon nanofibres," Stuart Licht PhD, leader of the research team, said. "Such nanofibres are used to make strong carbon composites, such as those used in the Boeing Dreamliner, high-end sports equipment, wind turbine blades and a host of other products."

Because of its efficiency, this low-energy process can be run using a few volts of electricity, sunlight and carbon dioxide. At its root, the system uses electrolytic syntheses to make the nanofibres. CO₂ is broken down in a high-temperature electrolytic bath of molten carbonates at 750°C. Atmospheric air is added to an electrolytic cell. Once there, the CO₂ dissolves when subjected to heat and direct current through electrodes of nickel and steel. The carbon nanofibres build up on the steel electrode, where they can be removed.

To power the syntheses, heat and electricity are produced through a hybrid solar-energy system. The system focuses the sun's rays on a photovoltaic solar cell to generate electricity and on a second system to generate heat and thermal energy, which raises the temperature of the electrolytic cell.

Licht estimates electrical energy costs of this 'solar thermal electrochemical process' to be around $1000 per ton of carbon nanofibre product, meaning the cost of running the system is said to be hundreds of times less than the value of product output.

"We calculate that with a physical area less than 10% the size of the Sahara Desert, our process could remove enough CO₂ to decrease atmospheric levels to those of the pre-industrial revolution within 10 years," he said.

Licht claims that the group has recently achieved is the ability to synthesise carbon fibres using even less energy than when the process was initially developed. "Carbon nanofibre growth can occur at less than 1V at 750°C, which for example is much less than the 3 to 5V used in the 1000°C industrial formation of aluminium," he said.

The team's biggest challenge will be to ramp up the process and gain experience to make consistently sized nanofibres. "We are scaling up quickly," he adds, "and soon should be in range of making tens of grams of nanofibres an hour."

Author
Tom Austin-Morgan

This material is protected by MA Business copyright
See Terms and Conditions.
One-off usage is permitted but bulk copying is not.
For multiple copies contact the sales team.