Effects of surface-chemical heterogeneity on molecular adsorption in and on single-walled carbon nanotubes

IEC 70

Radisav Vidic1, Seokjoon Kwon1, Feng Xue2, Tiffany Newsome3, and Eric Borguet4. (1) Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15260, (2) Surface Science Center, University of Pitsburgh, 219 Parkman Avenue, Pittsburgh, PA 15260, (3) Bennett College, (4) Chemistry Department, University of Pittsburgh, 219 Parkman Ave., Pittsburgh, PA 15260
The interactions of SWNT with their environment will determine many of their applications. As in the case of other nanoporous carbons, chemical and topological heterogeneity play major roles in determining the properties and function of SWNTs. Molecular interactions with SWNTs were investigated via the adsorption/desorption behavior of representative model non-polar (propane) and polar (acetone) volatile organic compounds (VOCs). The study revealed that the adsorption is controlled by oxygen- and hydrogen-containing functional groups exist on SWNT surface. The presence of these groups almost completely suppresses propane adsorption at 90K. These groups can be removed from SWNT by thermal treatment (> 500 K), leading to more than an order of magnitude increase in propane adsorption capacity, while little effect on acetone is observed.