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 nanotub es far Xe adsorption at 95 K. Infrared studies show the existence of carbox ylic acid and quinone groups on the nanotube surface prior to heating above 623 K. These groups decompose during heat treatment of nanotube sample fro m 623 to 1073 K producing CO, CO2, CH4 and H-2. The removal of a large numb er of these groups opens the entry ports fur adsorption on the inner surfac e of the nanotube and leads to dramatically enhanced Xe adsorption. (C) 200 0 Elsevier Science B.V. All rights reserved.