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 sp(2)-hybrid carbon skeleton. This is the key to high-efficiency tailoring of the CNTs with different length distributions (i.e., similar to 640, similar to 308, and similar to 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.