Low-Temperature Hydrogenation of Acetaldehyde to Ethanol on H-Precovered Au(111)

Gold-based classical high surface area catalysts have been widely investigated for hydrogenation reactions, but fundamental studies on model catalysts are lacking. We present experimental measurements of the reaction of hydrogen adatoms and adsorbed acetaldehyde on the Au(111) surface employing temperature-programmed desorption. Here, we show that chemisorbed hydrogen adatoms bind weakly with desorption peaks at similar to 110 K, indicating an activation energy for recombinative desorption of similar to 28 kJ/mol. We further demonstrate that acetaldehyde (CH(3)CHO) can be hydrogenated to ethanol (CH(3)CH(2)OH) on the H-atom-precovered Au(111) surface at cryogenic temperatures. Isotopic experiments employing D atoms indicate a lower hydrogenation reactivity.