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.