AVS 50th International Symposium
    Applied Surface Science Monday Sessions
       Session AS-MoA

Paper AS-MoA2
Adsorption and Dimerization of NO Inside of Single Walled Carbon Nanotubes - An Infrared Spectroscopic Study

Monday, November 3, 2003, 2:20 pm, Room 324/325

Session: Nanotube and Nanoparticle Characterization
Presenter: P. Kondratyuk, University of Pittsburgh
Authors: P. Kondratyuk, University of Pittsburgh
O. Byl, University of Pittsburgh
J.T. Yates, Jr., University of Pittsburgh
Correspondent: Click to Email
The physical adsorption of NO on purified (10,10) single walled carbon nanotubes was investigated at low temperatures by means of transmission infrared spectroscopy. Ozone treatment followed by annealing was used as a method of opening the entry ports for adsorption into the interior of the nanotubes. The IR spectra show that NO which is adsorbed inside of nanotubes exists exclusively in its dimer form, with no infrared bands of the monomer visible at a sensitivity level of 5 mole % NO. The internally adsorbed NO dimer species observed is cis-(NO)@sub 2@ with v@sub 1@(symmetric) = 1853 cm@super -1@ and v@sub 5@ (asymmetric) = 1754 cm@super -1@. Introduction of Xe into the system leads to selective displacement of the internally-bound cis-(NO)@sub 2@ dimer. A large spectroscopic red shift of the symmetric [-0.80%] and the asymmetric [-1.96%] modes for cis-(NO)@sub 2@ adsorbed inside of nanotubes (relative to gas phase cis-(NO)@sub 2@) points to the strong interaction of the dimer with the nanotube interior. The enthalpy of dissociation of the adsorbed dimer molecule is 15.1±0.7 kJ/mol.