FOURIER-TRANSFORM INFRARED REFLECTION-ABSORPTION SPECTROSCOPY STUDIES OF ADSORBATES AND SURFACE-REACTIONS - BRIDGING THE PRESSURE GAP BETWEEN SURFACE SCIENCE AND CATALYSIS

Recent development of in situ Fourier transform-infrared reflection absorption spectroscopy has provided us with a sensitive surface probe to study catalatic reactions on single crystal surfaces at elevated pressure. This method has been utilized in combination with (ex situ) photoemission and other probes to investigate the CO hydrogenation reaction over a potassium promoted Ru(001) surface. Potassium carbonate and formate are identified as-reaction intermediates. Isotope transient measurements demonstrate the activity of formate under equilibrium conditions. The comparison with the ultrahigh vacuum (UHV) model adsorbates allows us to establish that both formate and carbonate are bound to potassium and not to the ruthenium substrate. This suggests direct participation of the potassium in the synthesis of hydrocarbon species in this reaction.