Adsorption and dissociation of water on LaB6(100) investigated by surface vibrational spectroscopy

作者：Yorisaki Thomas; Tillekaratne Aashani; Ren Yuan; Moriya Yukihiro; Oshima Chuhei; Otani Shigeki; Trenary Michael^*

来源：Surface Science, 2012, 606(3-4): 247-252.

DOI：10.1016/j.susc.2011.09.025

• Lanthanum hexaboride
• Surface vibrational spectroscopy
• Reflection absorption infrared spectroscopy
• High resolution electron energy loss spectroscopy
• Water

The chemisorption of water (H2O and D2O) on a LaB6(100) surface was studied with reflection absorption infrared spectroscopy (RAIRS) and high resolution electron energy loss spectroscopy (HREELS). The clean surface was exposed to H2O and D2O at temperatures from 90 K to room temperature, and spectra were acquired after heating to temperatures as high as 1200 K. It was found that water molecularly adsorbs on the surface at 90 K as a monomer at low coverages and as amorphous solid water at higher coverages. Water adsorbs dissociatively at room temperature to produce surface hydroxyl species as indicated by OH/OD stretch peaks at 3676/2701 cm(-1). Room temperature adsorption also reveals low frequency loss features in HREEL spectra near 300 cm(-1) that are quite similar to results obtained following the dissociative adsorption of O-2. In the latter case, the loss features were attributed to the La - O stretch of O atoms bridge-bonded between two La atoms. In the case of dissociative adsorption of H2O, the low frequency loss features could be due to either the La - O vibrations of adsorbed O or of adsorbed OH.

• 出版日期2012-2