Selective removal of metallic single-walled carbon nanotubes with small diameters by using nitric and sulfuric acids

A selective removal of m-SWCNTs (single walled carbon nanotubes) with small diameters is reported by using HNO3/H2SO4 solution, which could be achieved by adjusting the treatment conditions. The result can be explained by the charge transfer from m-SWNCTs to NO2(super +) dissolved in the HNO3/H2SO4 solution in good agreement with the theoretical calculations.