Scientists at George Washington University, led by Stuart Licht, have discovered a novel method for purifying carbon nanotubes (CNTs) using microwave-driven plasma. This innovative approach offers a more efficient and sustainable alternative to conventional purification techniques.
The researchers found that when carbon nanotubes, derived from waste carbon dioxide, are microwaved, they form a distinctive yellow-white plasma. This plasma effectively oxidizes impurities, such as metals, electrolytes, and amorphous carbon, present in the nanotubes. The self-purification process is significantly faster and consumes less power compared to traditional plasma treatments.
The study, published on January 30, 2025, in the journal Nanoscale, highlights that the plasma forms when the nanotubes are heated, releasing electrons. This method is particularly effective with CNTs created directly from carbon dioxide via molten carbonate electrolysis, a process where CO2 is split into carbon nanotubes and oxygen. The incorporation of transition metals during electrolysis enhances the electrical conductivity and magnetic properties of the nanotubes, enabling them to absorb microwave energy more efficiently and reach the temperatures required for plasma formation. This breakthrough could pave the way for more sustainable and efficient production and purification of carbon nanotubes, with potential applications in various fields.