EVIDENCE FOR ACTIVATION OF THE C-O BOND OF METHANOL ON THE PD(111) SURFACE AFTER LOW-TEMPERATURE ADSORPTION

Direct evidence, using secondary ion mass spectroscopy (SIMS) supported by X-ray photoelectron spectroscopy (XPS), has been obtained for the activation of the C-O bond of methanol after adsorption at 110 K on the Pd left brace 111 right brace surface. In our experiments we find that the C-O bond dissociates after heating to 175 K leaving CH//3//a//d//s (methyl) and H//2O//a//d//s, as evidence by prominent SIMS signals at m/e 15 and 18, respectively. Methoxide (CH//3 O//a//d//s) is produced simultaneously and has been identified by its carbon 1s photoelectron binding energy. In addition to reporting the first observation of methanolic C-O bond activation on a well-defined transition-metal surface**1 we also report the discovery of a stable methyl species on Pd left brace 111 right brace as the surface is heated from 175 to 400 K.