Ethanol Dehydrogenation\non Pt/Cu(111) Surfaces

Reflection absorption infrared spectroscopy (RAIRS) was\nused to\ndirectly identify an ethoxy intermediate formed by the dry dehydrogenation\nof ethanol on a Pt/Cu(111) single-atom alloy surface. Temperature-programmed\nreaction spectroscopy was used to monitor reaction-limited desorption\nof acetaldehyde that follows from activation of a C–H bond\nof ethoxy. The RAIRS results for ethoxy formed on the Pt/Cu(111) surface\nwere compared to RAIR spectra of ethoxy at a coverage of 0.5 monolayer\nformed on oxidized Cu(111). Quantification of the ethoxy coverage\nfrom the RAIRS intensities indicated that it was less than the Pt\ncoverage on the Pt/Cu(111) surface. This is contrary to the expectation\nthat one Pt site could form multiple ethoxy molecules on Cu sites\nthrough spillover. Possible reasons for not detecting ethoxy spillover\nin these experiments are discussed.