Surface Chemistry of Ethanol on a Cu-Modified Co(10-12) Single Crystal Surface

Adsorption and surface reaction of ethanol on a Cu-modified Co(10-12) single crystal surface are studied using thermal desorption spectroscopy (TDS), X-ray photoelectron spectroscopy (XPS), and polarization-modulated infrared reflection-absorption spectroscopy (PM-IRAS). Charge transfer occurred from Cu to Co, leading to suppressed reactivity of the Co(10-12) surface. Dissociation of CH₃CH₂OH to CH₃CH₂O* and H* occurs minorly at 110 K, whereas molecular adsorption dominates. Upon heating, chemisorbed CH₃CH₂OH* undergoes both molecular desorption and CH₃CH₂OH* → CH₃CH₂O* + H*, CH₃CH₂OH* → CH₃CH₂* + OH* and CH₃CH₂O* → CH₃* + CO* + H* decomposition reactions. The barriers of these surface reactions follow an order of CH₃CH₂OH* → CH₃CH₂O* + H* < CH₃CH₂OH* → CH₃CH₂* + OH* < CH₃CH₂O* → CH₃* + CO* + H*. Gaseous CO and H₂ and surface atomic C species are the final products of the C₂H₅OH decomposition reaction. These results enrich our fundamental understanding of surface chemistry of ethanol on Co surfaces and CuCo-catalyzed reactions involving ethanol.