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 H₂.