Production of carbon nanotubes with marine manganese nodule as a versatile catalyst

Carbon nanotubes can be produced by pyrolysis of acetylene at 750 °C, using powdered naturally occurring marine manganese nodules as the catalyst. Helically coiled nanotubes can also be produced in a high yield by changing the experimental conditions. Compared to other catalysts, the mineral catalyst is cheap, convenient and versatile. The porous mineral phase is spontaneously collapsed at elevated temperature, and the catalytic metal cations, originally accommodated in the mineral, moved to the outer surface, where they aggregated to metallic nanoparticles available for the growth of the nanotubes.