Chemisorption-Isotherm Measurements at Electrode Surfaces by Quantitative High-Resolution Electron Energy Loss Spectroscopy
- 175 Downloads
The chemisorption isotherm of benzoquinone at a well-defined Pd(100) surface was obtained by quantitative high-resolution electron energy loss spectroscopy (HREELS). Extraction of surface-coverage information from HREELS required the normalization of integrated peak intensities to compensate for differences in the backscattered electron flux brought about by the organic adlayer. A common procedure rests on a match of the elastic-peak heights, but it fails for organic adsorbates since those introduce surface roughness that result in a higher stream of inelastically scattered electrons. A more accurate method is based on the equalization of the incident electron beam currents. This is attained only when the background intensities integrated over a peak-free spectral region are set equal to one another. The HREELS-generated isotherm was compared with that acquired by thin-layer electrochemical measurements; excellent agreement was observed.
KeywordsHigh-resolution electron energy loss spectroscopy Chemisorption isotherms Surface coverage measurements by HREELS Background-intensity normalization of HREEL spectra HREELS of benzoquinone chemisorbed on Pd(100) electrodes
This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, as follows: The HREELS spectral analysis and surface-coverage determination were supported through the Office of Science of the US Department of Energy under award no. DE-SC0004993; the TLE and HREELS experimental measurements were supported by The Welch Foundation (A-1064).
- 2.M.P. Soriaga, R.J. Barriga, in Handbook of surface imaging and visualization. Chapter 34, ed. by A.T. Hubbard (CRC Press, Boca Raton, 1995)Google Scholar
- 4.D.P. Woodruff, T.A. Delchar, Modern techniques of surface science (Cambridge University Press, New York, 1986)Google Scholar
- 6.H. Ibach, D.L. Mills, Electron energy loss spectroscopy and surface vibrations (Academic, New York, 1982)Google Scholar