Turning Greenhouse Gas into Carbon Nanotubes

A team of scientists at George Washington University (USA) has successfully developed a technology that directly converts CO₂ into carbon nanotubes (C2CNT) in a controlled manner by molten electrolysis using low-cost electrodes (nickel and steel) and low voltage. The synthesis consumes only CO₂ and electricity. The technology can be used not only to directly convert CO₂ in the air but also CO₂ emitted from industrial plants. The team is currently deploying C2CNT technology at pilot production scale at cement plants.

The team compared CO₂ emissions from conventional cement plants with those from cement plants equipped with C2CNT technology as follows:

• In a cement plant equipped with C2CNT technology, carbon nanotubes are produced by electrolysis of CO₂ in molten carbonate;
• A conventional cement plant emits 1.1 tonnes of CO₂ per tonne of cement produced;
• In a cement plant equipped with C2CNT technology, CO₂ is converted into a valuable CNT co-product;

With these results, the George Washington University team was awarded the international Carbon XPrize for research on converting CO₂ from thermal power plants into higher-value products.

Diagram of the electrolytic synthesis of carbon nanostructures from CO₂

Notes: (a) CO₂ from flue gas or air is dissolved in molten carbonate; (b) and (c) isotopic control of the formation of CNT carbon nanotubes/nanofibres – more valuable CNTs made from the common natural CO₂ . High oxide content forms tangles (d), while low oxide concentration forms straight nanotubes (f). (e) Bright nickel nucleation sites initiate CNT growth, identified by EDS. The images below show the application potential of CNTs and carbon nanofibres in the manufacture of aircraft, bridges, wind turbine blades, car tyres and batteries.

Summarised and translated by the Information Centre (according to Nanowerk)

Source: Vietnam Institute for Building Materials (vibm.vn)