Thermal decomposition of HSCH2CH2OH on Cu(111): identification and adsorption geometry of surface intermediates.
X-ray photoelectron spectroscopy has been employed to study the surface intermediates from the thermal decomposition of HSCH2CH2OH on Cu(111) at elevated temperatures. On the basis of the changes of the core-level binding energies of C, O, and S as a function of temperature, it is found that HSCH2CH2OH decomposes sequentially to form -SCH2CH2OH and -SCH2CH2O-. Theoretical calculations based on density functional theory for an unreconstructed one-layer copper surface suggest that -SCH2CH2OH is preferentially bonded at a 3-fold hollow site, with an adsorption energy lower than the cases at bridging and atop sites by 15.6 and 47.5 kcal x mol(-1), respectively. Other structural characteristics for the energy-optimized geometry includes the tilted C-S bond (14.1 degrees with respect to the surface normal), the C-C bond titled toward a bridging site, and the C-O bond pointed toward the surface. In the case of -SCH2CH2O- on Cu(111), the calculations suggest that the most probable geometry of the adsorbate has its S and O bonded at hollow and bridging sites, respectively. With respect to the surface normal, the angles of the S-C and O-C are 27.9 and 34.0 degrees.
Kuo
Kuan-Hung
KH
Department of Chemistry, National Cheng Kung University, 1, Ta Hsueh Road, Tainan, Taiwan, ROC.
Shih
Jain-Jung
JJ
Liao
Yung-Hsuan
YH
Fu
Tao-Wei
TW
Fan
Liang-Jen
LJ
Yang
Yaw-Wen
YW
Lin
Jong-Liang
JL