Oxygen Defect Engineering toward the Length-Selective Tailoring of Carbon Nanotubes via a Two-Step Electrochemical Strategy

A systematic study shows that carbon nanotubes (CNTs) with tunable lengths can be obtained by a simple two-step electrochemical approach via oxygen defect engineering. The preoxidation of CNTs in the H₂SO₄ electrolyte controllably introduces oxygen defects onto the sp²-hybrid carbon skeleton. This is the key to high-efficiency tailoring of the CNTs with different length distributions (i.e., ∼640, ∼308, and ∼130 nm) by the following oxidation in NaOH electrolyte. In addition, the short-cut CNTs are free of metal impurities and destructive damage to their tubular structures, displaying excellent dispersibility in various solvents. This nondestructive cutting and purification strategy is a low-cost robust pathway to the scalable manufacturing of length-selective CNTs for various practical applications.