Collect. Czech. Chem. Commun. 2001, 66, 1149-1163

Sulfur Adsorption and Reaction with a TiO2(110) Surface: O↔S Exchange and Sulfide Formation

Jan Hrbek*, Jose A. Rodriguez, Joseph Dvorak and Tomas Jirsak

Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973-5000, U.S.A.


Upon sulfur adsorption on TiO2(110) at 600 K, all surface oxygen is replaced by sulfur. High-resolution photoemission data show a complete loss of oxygen from the surface layer, a large binding energy shift and attenuation of Ti core levels, and the presence of three different S species. The bonding of sulfur is examined using first-principles density-functional calculations and the periodic supercell approach. At saturation the top layer of the oxide surface is converted to sulfide, with the majority of sulfur buckled above the Ti lattice plane and the remaining sulfur bonded in bridging sites. A mechanism for this self-limiting thermodynamically unlikely surface reaction is proposed.

Keywords: Sulfur; Titanium oxide; Photoemission spectroscopy; Sulfidation; DFT calculations; Surface reactions; Heterogeneous catalysis.

References: 33 live references.