AVS 53rd International Symposium
    Surface Science Monday Sessions
       Session SS1-MoM

Paper SS1-MoM8
Methanethiol Desulfurization on Titania-Supported Ni Clusters

Monday, November 13, 2006, 10:20 am, Room 2002

Session: Catalytic Chemistry of Hydrocarbons
Presenter: D.A. Chen, University of South Carolina
Authors: O. Ozturk, University of South Carolina
J.B. Park, University of South Carolina
D.A. Chen, University of South Carolina
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The hydrodesulfurization chemistry of methanethiol has been studied on Ni clusters supported on TiO@sub 2@(110). Ni clusters of different sizes and with uniform size distributions have been deposited on the titania substrate and characterized by scanning tunneling microscopy (STM). After heating methanethiol adsorbed on the Ni clusters to various temperatures, high resolution X-ray photoelectron spectroscopy (XPS) studies demonstrate that methyl thiolate is formed as a surface intermediate, and atomic sulfur remains on the surface after methyl thiolate decomposition. Furthermore, the S(2p) binding energies suggest that the surfaces of the Ni clusters have predominantly (110) structure. Temperature programmed desorption (TPD) experiments show that methane and hydrogen are the major gaseous products formed from methanethiol decomposition on Ni clusters of all sizes, and CO is also formed a minor product via oxidation of atomic carbon by lattice oxygen. Both XPS and TPD studies indicate that the larger, annealed Ni clusters have decreased activity compared to the smaller clusters deposited at room temperature; this loss of activity may be related to partial encapsulation of the Ni clusters by TiO@sub x@ upon heating.