Desulfurization and Structural Transformation of Thiophene on the Pt(111) Surface

The temperature dependence of near-edge x-ray-absorption fine-structure spectra above the C $K$ edge and S $L_{2,3}$ edge for thiophene (${\mathrm{C}}_4$ ${\mathrm{H}}_4$S) on Pt(111) reveals changes in the chemisorption geometry and the cleavage of the carbon-sulfur bond. Our results suggest the formation of a metallocycle intermediate after desulfurization with the S atom replaced by a Pt surface atom. The near-edge x-ray-absorption fine-structure results are corroborated by thermal-desorption, x-ray photoemission, and electron-energy-loss data.