METHYL FORMATION FROM METHANOL DECOMPOSITION ON Pd{111} AND Pt{111}

The decomposition of CH3OH adsorbed on Pd{111} and Pt{111} is compared as the surface is heated between 100 and 500 K. Using secondary ion mass spectrometry (SIMS) and thermal programmed desorption (TPD) it is suggested that an anomalous CH3+ ion signal observed previously by Akhter and White on oxygen precovered Pt{111} arises from the formation of a surface CH3 species resulting from activation of the C-O bond of CH3OH. This interpretation stems from a recent observation by Levis, Zhicheng and Winograd that CH3OH decomposes to CH3, OH and OCH3 on clean Pd{111} between 100 and 300 K. The results are discussed in terms of the relative ability of these metals to synthesize CH3OH from CO and H-2.