SURFACE VIBRATIONS OF ADSORBED INTERMEDIATES IN THE REACTION OF ALCOHOLS WITH CU(100)

High resolution electron energy loss spectroscopy has been used to study the structure and orientation of surface species formed in the reaction of methanol and ethanol with Cu(100). Each alcohol was found to react with atomic oxygen on Cu(100) below room temperature to form the stable surface species CH3OCu, and C2H5OCu, respectively. Both of these species were stable to approximately 370 K but decomposed at higher temperatures to yield gaseous products, and a clean surface. Vibrational assignments of the observed modes was made with reference to the energy loss spectra of atomic oxygen and the deuterated alcohols on Cu(100), and infrared gaseous spectra of the alcohols. By applying the surface dipole selection rule, we show that both alkoxide species are oriented normal to the surface, although the ethoxide species is nonlinear. These results are in agreement with published thermal desorption studies on copper, and give strong support for the role of surface alkoxide species as stable surface intermediates in alcohol oxidation on copper surfaces. © 1979.