Scanning tunnelling microscopic studies on the adsorption and decomposition of ethene on the reconstructed Pt(1 0 0)-hex-R0.7° surface

Adsorption and subsequent dehydrogenation of ethene on the hexagonally reconstructed Pt(1 0 0)-hex-R0.7° surface has been investigated using scanning tunnelling microscopy (STM) and low energy electron diffraction (LEED). Our results confirm that heterogeneous nucleation of the (1×1) domains occur when the hexagonal reconstruction is lifted during ethene adsorption on Pt(1 0 0). The (1×1) domains are highly anisotropic, and tend to grow in the [N 1] direction of the hexagonal reconstruction. (1 0 0)-hex-R0.7° surface was saturated with ethene at room temperature followed by heating to 900 K. LEED patterns and STM images taken after heating consistently show that the adsorbate formed on the Pt(1 0 0) surface during ethene exposure appears to desorb completely, leaving a clean hexagonally reconstructed surface. The twofold carbon–platinum coordination on Pt(1 0 0) seems to be a less likely precursor for graphite formation than the threefold configuration occupied by ethylidyne on the Pt(1 1 1).