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Homogenously dispersing single-walled carbon nanotubes (SWNTs) in solvents has been one critical step towards exploiting their exceptional properties in high-performance components. However, the solubility of SWNTs is severely limited by the inert tube surfaces and strong tube-tube van der Waals attractions. Starting with carbon nanotubides, i.e., negatively charged SWNTs reduced by alkali metals, we herein propose a sonication-free approach to prepare an aqueous dispersion of SWNTs. The approach combines the spontaneous dissolution of nanotubides in polar aprotic solvents with polyvinylpyrrolidone wrapping and dialysis in deionized H2O, which results in well-dispersed, neutralized SWNTs. The gelation of concentrated SWNT dispersion leads to the formation of hydrogels, which is subsequently transformed into SWNT aerogels through lyophilization. The prepared SWNT aerogels exhibit high-mass-sorption capacities for organic solvent absorption, paving the way towards harvesting the extraordinary properties of SWNTs.

Elastic and fatigue-resistant materials with a wide service temperature range are extremely needed in the crash cushion, automobile safety, and personal protective equipment. By combining radial freeze casting with carbon welding, single-walled carbon nanotube aerogels (SWCNTAs) with cellular structures are fabricated from a facile, scalable sol–gel method. The prepared SWCNTAs show a negative Poisson’s ratio and high energy loss efficiency under the uniaxial compressive strain. Furthermore, the SWCNTAs exhibit both outstanding fatigue resistance with negligible plastic deformation even after 105 compressive cycles and superior elasticity ranging from −100 to 300 °C in air, making the aerogels viable candidates for energy dissipation in extreme environments.

Non-magnetic metal nanoparticles have been previously applied for the growth of single-walled carbon nanotubes (SWNTs). However, the activation mechanisms of non-magnetic metal catalysts and chirality distribution of synthesized SWNTs remain unclear. In this work, the activation mechanisms of non-magnetic metal palladium (Pd) particles supported by the magnesia carrier and thermodynamic stabilities of nucleated SWNTs with different (n, m) are evaluated by theoretical simulations. The electronic metal–support interaction between Pd and magnesia upshifts the d-band center of Pd, which promotes the chemisorption and dissociation of carbon precursor molecules on the Pd surface, making the activation of magnesia-supported non-magnetic Pd catalysts for SWNT growth possible. To verify the theoretical results, a porous magnesia supported Pd catalyst is developed for the bulk synthesis of SWNTs by chemical vapor deposition. The chirality distribution of Pd-grown SWNTs is understood by operating both Pd–SWNT interfacial formation energy and SWNT growth kinetics. This work not only helps to gain new insights into the activation of catalysts for growing SWNTs, but also extends the use of non-magnetic metal catalysts for bulk synthesis of SWNTs.

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