HREELS study of the interaction of ethylene with Pt films supported on ZrO2(100) and ZnO(0001)

The adsorption and reaction of ethylene on epitaxial Pt films supported on ZrO2(100) and ZnO(0001) was studied using high-resolution electron energy-loss spectroscopy (HREELS). On the (111) oriented surfaces of the supported Pt films, ethylene was found to adsorb in both di-sigma and pi-bonded configurations at temperatures near 100 K. This result is in contrast to the interaction of ethylene with Pt(lll) where only the di-sigma species is stable at 100 K and suggests that the surfaces of the films contained a high concentration of steps and other defects. Both di-sigma and pi-bonded ethylene were also detected on Pt particles supported on ZrO2(100) at 130 K. On the supported Pt films and particles, adsorbed ethylene underwent dehydrogenation and rearrangement to form ethylidyne upon heating to 300 K. The results of this study serve to further demonstrate the utility of HREELS in characterizing adsorbates on model supported metal catalysts.