Directly mass-production growing method of CNT aerogel with superb liquid-absorption capability

Nano porous materials, such as grapheme sponge, foam and SiO₂ aerogel, have recently attracted a great deal of attention because of their light-weight, extremely high specific surface, and potential for heat insulation, noise reduction, energy-absorbing and energy-storage. Because carbon nanotube (CNT) has high aspect ratio, amazing thermal and electrical conduction^[1], it also plays important roles in constituting porous materials. Moreover, lots of studies have been done on CNT foams with most of them made from intermittent methods, such as sol-gel and chemical vapor deposition. Here, a kind of CNT aerogel, which is growing by floating catalyst chemical vapor deposition method (FCCVD), is introduced. In order to get ideal CNT aerogel, we modified growing conditions to control the CNTs fabrication in the reaction zone. The result shows that in hydrogen and argon atmosphere, ethanol with 1% ferrocene and thiophene atomized and injected in to quartz tube with the reaction zone temperature around 1300^oC will get excellent self-assembling interconnected 3D CNT network. After a certain period collection, network stacks at the tube end and form a cylindrical aerogel with 53 mm in height and 38 mm in diameter. This kind of aerogel gets 12.8 mg/cm³ in density and shows remarkable flexibility. What is more, the aerogel is super hydrophobic, which indicates that it will not absorb water and can collapse itself in moisture environment. It also has great capability of oil-absorption, which can absorb more than 90 times of its own weight of oil and organic solvent, such as acetone. It also has good sorption-squeezing and thermal stability properties, which means that the solvent absorbed can be squeezed out or burned. Thus, it could be a recyclable sorbent for oil and organic solvents. This CNT aerogel directly grows from gaseous phase rather than liquid phase (required in sol-gel method), which makes aerogel fabrication easier. Moreover, compared with other method, the FCCVD method can continuously produce, which means this is a low-cast and suitable for industrial production way to produce oils and organic solvents clean aerogel.