IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Wednesday Sessions
       Session SS+SC-WeM

Paper SS+SC-WeM10
Probing Chemical and Topological Heterogeneity of Carbonaceous Surfaces via Temperature Programmed Desorption of Simple Molecules from Model Carbonaceous Surfaces

Wednesday, October 31, 2001, 11:20 am, Room 122

Session: Adsorption on Semiconductor and Metal Oxide Surfaces
Presenter: J. Kwon, University of Pittsburgh
Authors: J. Kwon, University of Pittsburgh
R. Vidic, University of Pittsburgh
E. Borguet, University of Pittsburgh
Correspondent: Click to Email
Carbonaceous surfaces find applications in fields ranging from tribology to environmental remediation to catalysis. These surfaces are generally characterized by varying extent of chemical and topological heterogeneity that affects key elementary processe s such as adsorption and desorption. Temperature programmed desorption of model adsorbents (propane and acetone), representative of polar and non-polar organic compounds, was used to investigate the role of surface chemical and topological heterogeneity on the physical and chemical properties of model carbonaceous surfaces (air cleaved and plasma oxidized highly oriented pyrolytic graphite - HOPG). We observed that hydrogen and oxygen containing functional groups, which tend to block available adsorption sites, exist on air cleaved and plasma oxidized HOPG. Thermal treatment leads to removal of these groups and to over an order of magnitude increase in adsorption capacity. Thermal treatment (> 900 oC) of carbonaceous surfaces appears essential for maximum accessibility to adsorption sites. The surface defects induced by plasma oxidation yield greater surface area available for adsorption and higher energy sites. This novel approach promises a better understanding of chemically and topologically heterogeneous nanoporous carbons used in practical applications.