Facile C-O bond scission in alcohols on Zn surfaces

Interaction of methanol, ethanol, and 2-propanol with polycrystalline as we ll as (0001) surfaces of Zn has been investigated by photoelectron spectros copy and vibrational energy loss spectroscopy. All the alcohols show eviden ce for the condensed species along with the chemisorbed species at 80 K. Wi th increase in temperature to similar to 120 K, the condensed species desor bs, leaving the chemisorbed species which decomposes to give the alkoxy spe cies. The alkoxy species is produced increasingly at lower temperatures as we go from methanol to 2-propanol, the 2-propoxy species occurring even at 80 K. The alkoxy species undergo C-O bond scission giving rise to a hydroca rbon species and oxygen. The C-O bond cleavage occurs at a relatively low t emperature of similar to 150 K. The effect of preadsorbed oxygen is to stab ilize the methoxy species and prevent C-O bond scission. On the other hand, coadsorption of oxygen with methanol favors the formation of the methoxy s pecies and gives rise to hydrocarbon species arising from the C-O bond scis sion even at 80 K.