Enhancement of adsorption inside of single-walled nanotubes: opening the entry ports

Opening the ends of the single-walled carbon nanotube by thermal activation increases both the kinetic rate and the saturation capacity of the nanotubes for Xe adsorption at 95 K. Infrared studies show the existence of carboxylic acid and quinone groups on the nanotube surface prior to heating above 623 K. These groups decompose during heat treatment of nanotube sample from 623 to 1073 K producing CO, CO2, CH4 and H2. The removal of a large number of these groups opens the entry ports for adsorption on the inner surface of the nanotube and leads to dramatically enhanced Xe adsorption.