Scanning tunnelling microscopic studies on the adsorption and decomposition of ethene on the reconstructed Pt(100)-hex-R0.7 degrees surface

Adsorption and subsequent dehydrogenation of ethene on the hexagonally reco nstructed Pt(100)-hex-R0.7 degrees surface has been investigated using scan ning tunnelling microscopy (STM) and low energy electron diffraction (LEED) . Our results confirm that heterogeneous nucleation of the (1 x 1) domains occur when the hexagonal reconstruction is lifted during ethene adsorption on Pt(100). The (1 x 1) domains are highly anisotropic, and tend to grow in the [N 1] direction of the hexagonal reconstruction. The Pt(100)-hex-R0.7 degrees surface was saturated with ethene at room temp erature followed by heating to 900 K. LEED patterns and STM images taken af ter heating consistently show that the adsorbate formed on the Pt(100) surf ace during ethene exposure appears to desorb completely, leaving a clean he xagonally reconstructed surface. The twofold carbon-platinum coordination. on Pt(100) seems to be a less likely precursor for graphite formation than the threefold configuration occupied by ethylidyne on the Pt(111). (C) 2001 Published by Elsevier Science B,V.